Valve drive apparatus and supercharger having the same

ABSTRACT

In a valve drive apparatus, which drives a first valve and a second valve of a supercharger, a first rod is rotatably connected to a first valve lever shaft at one end part thereof to drive the first valve and is connected to a shaft at the other end part thereof, and a second rod is rotatably connected to a second valve lever shaft at one end part thereof to drive the second valve and is connected to a second member at the other end part thereof. A spring is placed between a first engaging part of the first member and a second engaging part of the second member and urges the first member and the second member to urge a first contact part of the first member and a second contact part of the second member toward each other.

CROSS REFERENCE TO RELATED APPLICATION

This application is based on and incorporates herein by referenceJapanese Patent Application No. 2013-95433 filed on Apr. 30, 2013,Japanese Patent Application No. 2013-95434 filed on Apr. 30, 2013, andJapanese Patent Application No. 2014-40374 filed on Mar. 3, 2014.

TECHNICAL FIELD

The present disclosure relates to a valve drive apparatus and asupercharger having the same.

BACKGROUND

Previously, a valve drive apparatus, which drives two valves of asupercharger, has been known. For example, JP2010-281271A discloses avalve drive apparatus, which has a single actuator that drives twovalves (first and second valves) of a two-stage supercharger. This valvedrive apparatus includes a link mechanism placed between the actuatorand the valves. A drive force of the actuator is transmitted to thevalves through the link mechanism.

In the valve drive apparatus of JP2010-281271A, the second valve isurged in a closing direction thereof by a spring and is thereby held ina valve closed state until the first valve is opened to a predeterminedopening degree or larger. When the first valve opens to thepredetermined opening degree or larger, the second valve is opened bythe link mechanism synchronously with the first valve. When the secondvalve is opened synchronously with the first valve, the urging force ofthe spring is applied to the first valve and the second valve. In thevalve drive apparatus of JP2010-281271A, the link mechanism is formedwith a large number of constituent members and is thereby complicated.Thus, the costs of the constituent members of the valve drive apparatusand manufacturing costs of the valve drive apparatus may bedisadvantageously increased.

Furthermore, depending on an action angle of a link node of the linkmechanism, a transmission efficiency of the drive force of the actuatormay possibly be deteriorated. JP2010-281271A does not disclose astructure, which improves the transmission efficiency of the driveforce.

When the second valve is opened, the urging force of the spring isapplied to an output shaft of the actuator through the link mechanism.Therefore, in a case where the second valve is mainly opened as theoperation of the internal combustion engine, the load of the actuator isincreased, and thereby the stress on the actuator may possibly beincreased. Furthermore, in a case where the actuator is an electricactuator, electric power consumption may possibly be increased.

Furthermore, in the range, which is from the starting of the opening ofthe first vale to the starting of the opening of the second valve, i.e.,the range, in which the first valve can be opened without receiving theurging force of the spring, is determined by a gap between the firstmember and the second member. A size of the gap between the first memberand the second member may vary depending on variations of theconstituent members, and thereby it may be difficult to accurately setthe above-described range.

SUMMARY

The present disclosure is made in view of the above disadvantages.

According to the present disclosure, there is provided a valve driveapparatus installed to a supercharger that includes a first valve, whichis rotatable about an axis of a first valve shaft, and a second valve,which is rotatable about an axis of a second valve shaft. The valvedrive apparatus is configured to drive the first valve and the secondvalve. The valve drive apparatus includes an actuator, a shaft, a firstmember, a second member, a first valve lever, a second valve lever, afirst rod, a second rod, and an urging device. The actuator includes anoutput shaft, which is movable in an axial direction of the outputshaft. The shaft is formed coaxially and integrally with the outputshaft or is formed separately from the output shaft. The first member isplaced along an axis of the shaft and includes a first contact part anda first engaging part. The second member is placed along the axis of theshaft and includes a second contact part and a second engaging part. Thesecond contact part is contactable with the first contact part. Thefirst valve lever includes a first valve lever shaft, which is rotatableintegrally with the first valve shaft. An axis of the first valve levershaft is parallel to the axis of the first valve shaft and is placed ata location that is spaced from the axis of the first valve shaft by afirst predetermined distance. The second valve lever includes a secondvalve lever shaft, which is rotatable integrally with the second valveshaft. An axis of the second valve lever shaft is parallel to the axisof the second valve shaft and is placed at a location that is spacedfrom the axis of the second valve shaft by a second predetermineddistance. The first rod is rotatably connected to the first valve levershaft at one end part of the first rod and is connected to the shaft orthe first member at another end part of the first rod, which is oppositefrom the one end part of the first rod. The second rod is rotatablyconnected to the second valve lever shaft at one end part of the secondrod and is connected to the second member at another end part of thesecond rod, which is opposite from the one end part of the second rod.The urging device is placed between the first engaging part and thesecond engaging part and urges the first member and the second member tourge the first contact part and the second contact part toward eachother.

According to the present disclosure, there is also provided a valvedrive apparatus installed to a supercharger that includes a first valve,which is rotatable about an axis of a first valve shaft, and a secondvalve, which is rotatable about an axis of a second valve shaft. Thevalve drive apparatus is configured to drive the first valve and thesecond valve. The valve drive apparatus includes an actuator, a firstdrive lever, a second drive lever, a first valve lever, a second valvelever, a first rod, a second rod, a first predetermined shape portion, asecond predetermined shape portion, and an urging device. The actuatorincludes an output shaft, which is rotatable about an axis of the outputshaft. The first drive lever includes a first drive lever shaft, whichis rotatable integrally with the output shaft. An axis of the firstdrive lever shaft is parallel to the axis of the output shaft and isplaced at a location that is spaced from the axis of the output shaft bya first predetermined distance. The second drive lever includes a seconddrive lever shaft, which is rotatable relative to the output shaft. Anaxis of the second drive lever shaft is parallel to the axis of theoutput shaft and is placed at a location, which is spaced from the axisof the output shaft by a second predetermined distance. The first valvelever includes a first valve lever shaft, which is rotatable integrallywith the first valve shaft. An axis of the first valve lever shaft isparallel to the axis of the first valve shaft and is placed at alocation, which is spaced from the axis of the first valve shaft by athird predetermined distance. The second valve lever includes a secondvalve lever shaft, which is rotatable integrally with the second valveshaft. An axis of the second valve lever shaft is parallel to the axisof the second valve shaft and is placed at a location, which is spacedfrom the axis of the second valve shaft by a fourth predetermineddistance. The first rod that is rotatably connected to the first drivelever shaft at one end part of the first rod and is rotatably connectedto the first valve lever shaft at another end part of the first rod,which is opposite from the one end part of the first rod. The second rodis rotatably connected to the second drive lever shaft at one end partof the second rod and is rotatably connected to the second valve levershaft at another end part of the second rod, which is opposite from theone end part of the second rod. The first predetermined shape portion isformed at a corresponding location of the first drive lever, which isspaced from the axis of the output shaft by a predetermined distance.The second predetermined shape portion is formed in the second drivelever and is contactable with the first predetermined shape portion. Theurging device is placed between the first drive lever and the seconddrive lever and urges the first drive lever and the second drive leverto move the first predetermined shape portion and the secondpredetermined shape portion toward each other.

According to the present disclosure, there is also provided asupercharger, which includes a compressor, a turbine, a first valve, asecond valve and one of the above-described valve drive apparatuses. Thecompressor is installed in an intake passage, which guides intake air toan internal combustion engine. The turbine is installed in an exhaustpassage, which conducts exhaust gas outputted from the internalcombustion engine. The turbine rotates the compressor when the turbineis rotated upon supply of the exhaust gas to the turbine. The firstvalve is installed in an exhaust flow path, which guides the exhaust gasfrom the internal combustion engine to the turbine. The first valveopens or closes the exhaust flow path through rotation of the firstvalve about an axis of a first valve shaft. The second valve isinstalled in a bypass flow path that connects between one side of theturbine, at which the internal combustion engine is located, and anopposite side of the turbine, which is opposite from the internalcombustion engine, in the exhaust passage, while the bypass flow pathbypasses the turbine. The second valve opens or closes the bypass flowpath through rotation of the second valve about an axis of a secondvalve shaft. The first valve lever is rotatable integrally with thefirst valve shaft to drive the first valve, and the second valve leveris rotatable integrally with the second valve shaft to drive the secondvalve.

According to the present disclosure, there is also provided asupercharger, which includes a first compressor, a second compressor, afirst turbine, a second turbine, a first valve, a second valve, and oneof the above-described valve drive apparatuses. The first compressor andthe second compressor are installed in an intake passage, which guidesintake air to an internal combustion engine. The first turbine isinstalled in an exhaust passage, which conducts exhaust gas outputtedfrom the internal combustion engine. The first turbine rotates the firstcompressor when the first turbine is rotated upon supply of the exhaustgas to the first turbine. The second turbine is installed in the exhaustpassage. The second turbine rotates the second compressor when thesecond turbine is rotated upon supply of the exhaust gas to the secondturbine. The first valve is installed in one of a first exhaust flowpath, which guides the exhaust gas from the internal combustion engineto the first turbine, and a second exhaust flow path, which guides theexhaust gas from the internal combustion engine to the second turbine.The first valve opens or closes the one of the first exhaust flow pathand the second exhaust flow path through rotation of the first valveabout an axis of a first valve shaft. The second valve is installed in abypass flow path that connects between one side of the first turbine andthe second turbine, at which the internal combustion engine is located,and an opposite side of the first turbine and the second turbine, whichis opposite from the internal combustion engine, in the exhaust passage,while the bypass flow path bypasses the first turbine and the secondturbine. The second valve opens or closes the bypass flow path throughrotation of the second valve about an axis of a second valve shaft. Thefirst valve lever is rotatable integrally with the first valve shaft todrive the first valve, and the second valve lever is rotatableintegrally with the second valve shaft to drive the second valve.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings described herein are for illustration purposes only and arenot intended to limit the scope of the present disclosure in any way.

FIG. 1A is a cross-sectional view of a valve drive apparatus and asupercharger according to a first embodiment of the present disclosure;

FIG. 1B is a cross-sectional view taken along line IB-IB in FIG. 1A;

FIG. 2 is a schematic diagram showing the supercharger, to which thevalve drive apparatus of the first embodiment is installed;

FIG. 3 is a schematic diagram showing the valve drive apparatus of thefirst embodiment;

FIG. 4A is a schematic diagram showing the valve drive apparatus of thefirst embodiment in an operational state where a first valve and asecond valve are both closed;

FIG. 4B is a diagram indicating a corresponding state of thesupercharger, which corresponds to FIG. 4A;

FIG. 5A is a schematic diagram showing the valve drive apparatus of thefirst embodiment in an operational state where the actuator is drivenfor a predetermined amount;

FIG. 5B is a diagram indicating a corresponding state of thesupercharger, which corresponds to FIG. 5A;

FIG. 6A is a schematic diagram showing the valve drive apparatus of thefirst embodiment in a state where the actuator is driven for apredetermined amount from an operational state shown in FIG. 5A;

FIG. 6B is a diagram indicating a corresponding state of thesupercharger, which corresponds to FIG. 6A;

FIG. 7A is a diagram showing a relationship between a drive amount ofthe actuator of the valve drive apparatus and opening degrees of thefirst and second valves;

FIG. 7B is a diagram showing a relationship between the drive amount ofthe actuator and a drive force of the actuator;

FIG. 8 is a diagram showing a relationship between a rotational speed ofan internal combustion engine provided with the valve drive apparatus ofthe first embodiment and a brake mean effective pressure (BMEP) or atorque;

FIG. 9 is a schematic diagram showing a valve drive apparatus accordingto a second embodiment of the present disclosure;

FIG. 10 is a schematic diagram showing a valve drive apparatus accordingto a third embodiment of the present disclosure;

FIG. 11 is a schematic diagram showing a valve drive apparatus accordingto a fourth embodiment of the present disclosure;

FIG. 12 is a schematic diagram showing a valve drive apparatus accordingto a fifth embodiment of the present disclosure;

FIG. 13A is a schematic view showing a supercharger provided with avalve drive apparatus according to a sixth embodiment of the presentdisclosure;

FIG. 13B is a schematic view showing a supercharger provided with avalve drive apparatus according to a seventh embodiment of the presentdisclosure;

FIG. 14 is a schematic diagram showing a valve drive apparatus and asupercharger according to an eighth embodiment of the presentdisclosure;

FIG. 15 is a schematic diagram showing a valve drive apparatus and asupercharger according to a ninth embodiment of the present disclosure;

FIG. 16 is a view taken in a direction of an arrow XVI in FIG. 15;

FIG. 17 is a view taken in a direction of an arrow XVII in FIG. 15;

FIG. 18 is a view taken in a direction of an arrow XVIII in FIG. 15;

FIG. 19 is a cross-sectional view taken along line XIX-XIX in FIG. 15;

FIG. 20 is a cross-sectional view taken along line XX-XX in FIG. 15;

FIG. 21A is a diagram showing a valve closed state of a first valve anda valve closed state of a second valve according to the ninthembodiment;

FIG. 21B is a diagram showing an operational state where an actuator isrotated for a predetermined amount from an operational state shown inFIG. 21A;

FIG. 22A is a diagram showing an operational state where the actuator isrotated for a predetermined amount from the operational state shown inFIG. 21B;

FIG. 22B is a diagram showing an operational state where the actuator isrotated for a predetermined amount from the operational state shown inFIG. 22A;

FIG. 23A is a diagram showing a relationship between an angle of theactuator and opening degrees of the first and second valves;

FIG. 23B is a diagram showing a relationship between the angle of theactuator and a drive force of the actuator;

FIG. 24 is a schematic diagram showing a valve drive apparatus accordingto a tenth embodiment of the present disclosure; and

FIG. 25 is a schematic diagram showing a valve drive apparatus accordingto an eleventh embodiment of the present disclosure.

DETAILED DESCRIPTION

Various embodiments of the present disclosure will be described withreference to the accompanying drawings. In the following embodiments,similar components will be indicated by the same reference numerals andwill not be described redundantly for the sake of simplicity.

First Embodiment

FIGS. 1A to 7 show a valve drive apparatus according to a firstembodiment of the present disclosure.

As shown in FIG. 1A, the valve drive apparatus 1 is installed to, forexample, a supercharger 3, which supercharges intake air to an internalcombustion engine (hereinafter referred to as an engine) 2 of a vehicle.The supercharger 3 supercharges the intake air to the engine 2 for thepurpose of increasing an output of the engine 2, increasing a torque ina practical rotational speed range of the engine 2, and improving fuelconsumption.

An intake conduit 4 is connected to the engine 2. An intake conduit 5 isprovided on a side of the intake conduit 4, which is opposite from theengine 2. An intake opening (not shown), which is opened to theatmosphere, is formed in an end part of the intake conduit 5, which isopposite from the intake conduit 4. An intake passage 6 is formed in aninside of the intake conduit 4 and an inside of the intake conduit 5.The intake passage 6 guides the air (hereinafter referred to as intakeair), which is drawn from the intake opening, to the engine 2.

An exhaust conduit 7 is connected to the engine 2. An exhaust conduit 8is communicated to the atmosphere through an exhaust emission purifier 9and an exhaust opening of the exhaust conduit 8. The exhaust emissionpurifier 9 includes a catalyst (not shown). An exhaust passage 10 isformed in an inside of the exhaust conduit 7 and an inside of theexhaust conduit 8. The exhaust passage 10 conducts the exhaust gas,which contains combustion gas generated during the operation of theengine 2. The exhaust gas is purified through the exhaust emissionpurifier 9 and is released to the atmosphere through the exhaustopening.

The supercharger 3 includes a compressor 11, a compressor housing 12, aturbine 13, a turbine housing 14, a bearing 15, a shaft 16, a firstvalve 17, and a second valve 18.

The compressor 11 is made of metal (e.g., aluminum) and is placedbetween the intake conduit 4 and the intake conduit 5 in the intakepassage 6. The compressor 11 includes a tubular portion 111 and aplurality of blades 112. The tubular portion 111 is configured into atubular form, which has an increasing outer diameter that increases fromone end part to the other end part of the tubular portion 111. Eachblade 112 is configured into a curved plate form. The blade 112 isformed in an outer wall of the tubular portion 111 and extends from theone end part of the tubular portion 111 to the other end part of thetubular portion 111. The blades 112 are arranged one after another atgenerally equal intervals in a circumferential direction of the tubularportion 111. The compressor 11 is received in the compressor housing 12.

The compressor housing 12 is placed between the intake conduit 4 and theintake conduit 5. The compressor housing 12 is made of, for example,metal. The compressor housing 12 includes a scroll 121. The scroll 121is configured into an annular form (a ring form), which is placed on aradially outer side of the blades 112 of the compressor 11 and extendsin a circumferential direction around the blades 112. Thereby, theintake air is guided from the intake conduit 5 to the intake conduit 4through the compressor 11 and the scroll 121 located in the inside ofthe compressor housing 12.

The turbine 13 is made of, for example, nickel base heat resisting steeland is placed between the exhaust conduit 7 and the exhaust conduit 8 inthe exhaust passage 10. The turbine 13 includes a tubular portion 131and a plurality of blades 132. The tubular portion 131 is configuredinto a tubular form, which has an increasing outer diameter thatincreases from one end part to the other end part of the tubular portion131. Each blade 132 is configured into a curved plate form. The blade132 is formed in an outer wall of the tubular portion 131 and extendsfrom the one end part of the tubular portion 131 to the other end partof the tubular portion 131. The blades 132 are arranged one afteranother at generally equal intervals in a circumferential direction ofthe tubular portion 131. The turbine 13 is received in the turbinehousing 14.

The turbine housing 14 is placed between the exhaust conduit 7 and theexhaust conduit 8. The turbine housing 14 is made of metal (e.g., ironmetal, which contains nickel). The turbine housing 14 includes a firstscroll 141 and a second scroll 142. The first scroll 141 is configuredinto an annular form (a ring form), which is placed on a radially outerside of the blades 132 and extends in a circumferential direction aroundthe blades 132. Similarly, the second scroll 142 is configured into anannular form (a ring form), which is placed on the radially outer sideof the blades 132 and extends in the circumferential direction aroundthe blades 132. The second scroll 142 is formed on an axial side of thefirst scroll 141 where the one end part of the tubular portion 131 islocated.

As shown in FIG. 1B, a first flow path 143, a second flow path 144, anda third flow path 145 are formed in the turbine housing 14. The firstflow path 143 connects between the inside of the exhaust conduit 7 andthe first scroll 141. The second flow path 144 extends along the firstflow path 143 and has one end part connected to the second scroll 142.An opening 146 is formed in a partition wall, which partitions betweenthe first flow path 143 and the second flow path 144. Therefore, theother end part of the second flow path 144 is connected to the inside ofthe exhaust conduit 7 through the opening 146 and the first flow path143.

The third flow path 145 connects the first scroll 141 and the secondscroll 142 to the inside of the exhaust conduit 8 and extends along thesecond flow path 144. The turbine 13 is placed in the third flow path145 at a corresponding location, which is adjacent to the first scroll141 and the second scroll 142. An opening 147 is formed in a partitionwall, which partitions between the second flow path 144 and the thirdflow path 145. Thereby, the second flow path 144 is connected to thethird flow path 145 through the opening 147 while bypassing the turbine13.

With the above-described construction, the exhaust gas, which isoutputted from the engine 2, can flow to the exhaust conduit 8 throughthe inside of the exhaust conduit 7, the first flow path 143, the firstscroll 141, the turbine 13, and the third flow path 145. Furthermore,the exhaust gas, which is outputted from the engine 2, can flow to theexhaust conduit 8 through the inside of the exhaust conduit 7, the firstflow path 143, the opening 146, the second flow path 144, the secondscroll 142, the turbine 13, and the third flow path 145. Here, the firstflow path 143, the opening 146, the second flow path 144, and the secondscroll 142 serve as an exhaust flow path of the present disclosure.Furthermore, the exhaust gas, which is outputted from the engine 2, canflow to the exhaust conduit 8 through the inside of the exhaust conduit7, the first flow path 143, the opening 146, the second flow path 144,the opening 147, and the third flow path 145. Here, the second flow path144, the opening 147, and the third flow path 145 serve as a bypass flowpath of the present disclosure, which connects in the exhaust passage 10between one side (upstream side) of the turbine 13, at which the engine2 is located, and an opposite side (downstream side) of the turbine 13,which is opposite from the engine 2, while the bypass flow path bypassesthe turbine 13.

FIG. 2 schematically shows the structure of the supercharger 3.

The bearing 15 is made of, for example, metal and is placed between thecompressor housing 12 and the turbine housing 14. The shaft 16 is madeof, for example, metal and is configured into a rod form. The shaft 16coaxially connects between the tubular portion 111 and the tubularportion 131. The shaft 16 is rotatably supported by the bearing 15.Thereby, the compressor 11 and the turbine 13 can rotate integrally withthe shaft 16.

When the exhaust gas, which is outputted from the first scroll 141, andthe exhaust gas, which is outputted from the second scroll 142, collidesagainst the blades 132 of the turbine 13, the turbine 13 is rotated.Thereby, the compressor 11 is rotated, so that the intake air, which ispresent in the intake conduit 5, is compressed and is guided to theengine 2. In the present embodiment, an intercooler 19 is placed in theintake passage 6 between the compressor housing 12 and the engine 2. Theintercooler 19 cools the intake air, the temperature of which isincreased upon compression through the compressor 11. Thus, the densityof the intake air is increased, and thereby the larger amount of intakeair can be supplied to the engine 2.

In the present embodiment, a throttle valve 20 is placed in the intakepassage 6 between the intercooler 19 and the engine 2. The throttlevalve 20 can open and close the intake passage 6. An electronic controlunit (hereinafter referred to as an ECU) 21 is connected to the throttlevalve 20. The ECU 21 is a small computer, which includes a processor, astorage device(s) and an input/output device. The ECU 21 runs a programstored in the storage device to execute various computations based onsignals received from sensors installed in corresponding components ofthe vehicle to control corresponding devices of the vehicle, so that theECU 21 controls the entire vehicle. The ECU 21 controls the operation(the opening degree) of the throttle valve 20 to adjust the amount ofintake air supplied to the engine 2.

The first valve 17 is made of, for example, metal and is placed at alocation that is adjacent to the opening 146 of the second flow path144. The first valve includes an arm 171, a valve element 172 and afirst valve shaft 173. The arm 171 is configured into a rod form. Thevalve element 172 is provided at one end part of the arm 171. The firstvalve shaft 173 is configured into a cylindrical tubular form and isintegrated with the arm 171 such that one end part of the first valveshaft 173 is connected to the other end part of the arm 171. The firstvalve shaft 173 is installed to the turbine housing 14 such that theother end part of the first valve shaft 173 is exposed to the outside ofthe turbine housing 14, and the first valve shaft 173 is rotatable aboutan axis of the first valve shaft 173. In this way, when the first valveshaft 173 is rotated about the axis of the first valve shaft 173, thevalve element 172 is moved toward or away from the opening 146. When thevalve element 172 contacts a peripheral edge part of the opening 146,the exhaust flow path is held in a closed state (a fully closed state, avalve closed state). In contrast, when the valve element 172 is movedaway from the peripheral edge part of the opening 146, the exhaust flowpath is placed in an open state (a valve open state).

In the valve closed state of the first valve 17, the exhaust gas isguided to the turbine 13 through the first flow path 143 and the firstscroll 141 to rotate the turbine 13. In contrast, in the valve openstate of the first valve 17, the exhaust gas is guided to the turbine 13through the first flow path 143, the opening 146, the second flow path144, the first scroll 141, and the second scroll 142 to rotate theturbine 13. As discussed above, the first valve 17 functions as a changevalve and controls the amount of exhaust gas supplied to the turbine 13.Therefore, in the present embodiment, the supercharger 3 is a variabledisplacement supercharger.

The second valve 18 is made of, for example, metal and is placed at alocation that is adjacent to the opening 147 of the third flow path 145.The second valve 18 includes an arm 181, a valve element 182 and asecond valve shaft 183. The arm 181 is configured into a rod form. Thevalve element 182 is provided at one end part of the arm 181. The secondvalve shaft 183 is configured into a generally cylindrical tubular formand is integrated with the arm 181 such that one end part of the secondvalve shaft 183 is connected to the other end part of the arm 181. Thesecond valve shaft 183 is installed to the turbine housing 14 such thatthe other end part of the second valve shaft 183 is exposed to theoutside of the turbine housing 14, and the second valve shaft 183 isrotatable about an axis of the second valve shaft 183. In this way, whenthe second valve shaft 183 is rotated about the axis of the second valveshaft 183, the valve element 182 is moved toward or away from theopening 147. When the valve element 182 contacts a peripheral edge partof the opening 147, the bypass flow path is held in a closed state (afully closed state, a valve closed state). In contrast, when the valveelement 182 is moved away from the peripheral edge part of the opening147, the bypass flow path is placed in an open state (a valve openstate).

The moving direction of the valve element 172 of the first valve 17 awayfrom the peripheral edge part of the opening 146 will be hereinafteralso referred to as a valve opening direction of the first valve 17.Also, the moving direction of the valve element 182 of the second valve18 away from the peripheral edge part of the opening 147 will behereinafter also referred to as a valve opening direction of the secondvalve 18. Furthermore, the moving direction of the valve element 172 ofthe first valve 17 toward the peripheral edge part of the opening 146will be hereinafter also referred to as a valve closing direction of thefirst valve 17. Also, the moving direction of the valve element 182 ofthe second valve 18 toward the peripheral edge part of the opening 147will be hereinafter also referred to as a valve closing direction of thesecond valve 18.

In the state where the first valve 17 is in the valve open state, andthe second valve 18 is in the valve closed sate, the exhaust gas isguided to the turbine 13 through the first flow path 143, the opening146, the second flow path 144, the first scroll 141, and the secondscroll 142 to rotate the turbine 13. In contrast, in the state where thefirst valve 17 and the second valve 18 are both in the open state, aportion of the exhaust gas in the second flow path 144 is conducted tothe third flow path 145 through the opening 147. Therefore, therotational speed of the turbine 13 is reduced, and thereby thesupercharging pressure is reduced. In this way, it is possible to limitthe excessive increase of the supercharging pressure. As discussedabove, the second valve 18 functions as a waste gate valve and controlsthe amount of exhaust gas, which bypasses the turbine 13.

As shown in FIG. 3, the valve drive apparatus 1 includes an actuator 30,a shaft (also referred to as a shaft portion) 35, a first member 40, asecond member 50, a first valve lever 61, a second valve lever 62, afirst rod 71, a second rod 72, a spring (serving as an urging device anda resilient member) 81, and a gap forming portion 90.

The actuator 30 includes a housing 31 and an output shaft 32. The outputshaft 32 is configured into a rod form. The output shaft 32 is receivedin the housing 31 and is axially reciprocatable. In the presentembodiment, when an electric power is supplied to the actuator 30, theactuator 30 axially drives, i.e., axially reciprocates the output shaft32. The actuator 30 is installed to the supercharger 3 such that thehousing 31 is fixed to the compressor housing 12.

The ECU 21 controls the electric power supplied to the actuator 30 tocontrol the axial movement of the output shaft 32.

The shaft 35 is configured into a rod form and is coaxially andintegrally formed with the output shaft 32 of the actuator 30. In thisway, the shaft 35 can axially reciprocate integrally with the outputshaft 32. The shaft 35 serves as an intermediate shaft placed betweenthe output shaft 32 and the first and second valves 17, 18. Furthermore,the shaft 35 includes a shaft part 351, which is configured into agenerally cylindrical tubular form and extends in a directionperpendicular to the axis.

The first member 40 includes a main body 41. The main body 41 isconfigured into a generally circular plate form. A center part of oneside surface of the main body 41 is connected to, i.e., joined to an endpart of the shaft 35, which is opposite from the actuator 30. That is,the main body 41 is placed along the axis of the shaft 35. In this way,the main body 41 can axially reciprocate together with the output shaft32 and the shaft 35. In other words, the main body 41 is movableintegrally with the output shaft 32 and the shaft 35. A first contactpart 411 is formed in the other side surface of the main body 41. Afirst engaging part 412 is formed in the one side surface of the mainbody 41.

The second member 50 includes a main body 51, a tubular portion 52, andan extension 53. The main body 51 is configured into a generallycircular plate form. A second contact part 511 is formed in one sidesurface of the main body 51. A shaft part 512 is formed in the main body51. The shaft part 512 is configured into a generally cylindricaltubular form and extends in a direction (radial direction), which isparallel to a plane of the main body 51.

The tubular portion 52 is configured into a tubular form and extendsfrom an outer peripheral edge part of the one side surface of the mainbody 51 in a direction (a plate thickness direction of the main body51), which is perpendicular to the plane of the main body 51. Theextension 53 is configured into an annular form and radially inwardlyextends from an opposite end part of the tubular portion 52, which isopposite from the main body 51. A second engaging part 531 is formed ina surface of the extension 53, which is located on a side where the mainbody 51 is placed.

The second member 50 is placed along the axis of the shaft 35 such thatthe first member 40 is placed between the second contact part 511 andthe second engaging part 531, and the first contact part 411 of thefirst member 40 is opposed to the second contact part 511. Therefore,when the second member 50 and the first member 40 are axially movedrelative to each other, the second contact part 511 and the firstcontact part 411 can contact with each other.

The first valve lever 61 includes a main body 611, and a first valvelever shaft 612. The main body 611 is configured into a rod form and isfixed to the first valve shaft 173 at one end part of the main body 611.In this way, the main body 611 (the first valve lever 61) can rotateintegrally with the first valve shaft 173. Thus, when the main body 611is rotated integrally with the first valve shaft 173, the first valve 17is opened or closed.

The first valve lever shaft 612 is configured into a generallycylindrical tubular form and is provided at the other end part of themain body 611. An axis of the first valve lever shaft 612 is parallel tothe axis of the first valve shaft 173 and is placed at a location, whichis spaced from the axis of the first valve shaft 173 by a firstpredetermined distance D1.

The second valve lever 62 includes a main body 621, and a second valvelever shaft 622. The main body 621 is configured into a rod form and isfixed to the second valve shaft 183 at one end part of the main body621. In this way, the main body 621 (the second valve lever 62) canrotate integrally with the second valve shaft 183. Thus, when the mainbody 621 is rotated integrally with the second valve shaft 183, thesecond valve 18 is opened or closed.

The second valve lever shaft 622 is configured into a generallycylindrical tubular form and is provided at the other end part of themain body 621. An axis of the second valve lever shaft 622 is parallelto the axis of the second valve shaft 183 and is placed at a location,which is spaced from the axis of the second valve shaft 183 by a secondpredetermined distance D2.

The first rod 71 is configured into a rod form. The first rod 71 isrotatably connected to the first valve lever shaft 612 at one end partof the first rod 71 and is rotatably connected to the shaft part 351 ofthe shaft 35 at the other end part of the first rod 71.

The second rod 72 is configured into a rod form. The second rod 72 isrotatably connected to the second valve lever shaft 622 at one end partof the second rod 72 and is rotatably connected to the shaft part 512 ofthe second member 50 at the other end part of the second rod 72.

The spring 81 is made of a resilient member that is made of, forexample, metal. The spring 81 is configured into a coil form. That is,the spring 81 is a coil spring. The spring 81 is placed on a radiallyouter side of the shaft 35 and is held between the first member 40 andthe extension 53 of the second member 50. The spring 81 is engaged withthe first engaging part 412 of the first member 40 at one end part ofthe spring 81 and is engaged with the second engaging part 531 of thesecond member 50 at the other end part of the spring 81. In the presentembodiment, the spring 81 has a predetermined modulus of elasticity andhas an axially expanding force. Specifically, the spring 81 urges thefirst member 40 and the second member 50 to urge the first contact part411 and the second contact part 511 toward each other.

In the present embodiment, the gap forming portion 90 is formed in thesecond member 50. The gap forming portion 90 includes a screw part 91and a nut 92. The screw part 91 is configured into a generallycylindrical rod form and has a male thread in an outer peripheral wallof the screw part 91. The screw part 91 is threaded into a threadedhole, which is formed in the main body 51 (the second contact part 511)and has a female thread formed in an inner peripheral wall of thethreaded hole. When the screw part 91 is threaded into the threaded holeof the main body 51, the screw part 91 projects from the second contactpart 511 by a predetermined amount toward the first contact part 411.The amount of projection of the screw part 91 from the second contactpart 511 toward the first contact part 411 can be adjusted by adjustingthe amount of insertion of the screw part 91 into the threaded hole ofthe main body 51.

The nut 92 is configured into an annular form and has a female thread,which corresponds to the male thread of the screw part 91, in an innerperipheral wall of the nut 92. The nut 92 is threadably installed to thescrew part 91 from an end of the screw part 91, which is opposite fromthe first contact part 411, such that the nut 92 contacts the main body51. In this way, the screw part 91 is non-displaceably held relative tothe main body 51.

As shown in FIGS. 3 and 4A, in the state where the first valve 17 andthe second valve 18 are both held in the valve closed state (fullyclosed state), the screw part 91 and the first contact part 411 arespaced from each other. In contrast, as shown in FIG. 5A, in the statewhere the second valve 18 is held in the valve closed state (the fullyclosed state), when the first valve 17 is opened for a predeterminedamount, the screw part 91 and the first contact part 411 contact witheach other. At this time, a predetermined gap is formed between thefirst contact part 411 and the second contact part 511.

In the present embodiment, as shown in FIG. 3, the first valve lever 61and the second valve lever 62 are formed such that the firstpredetermined distance D1 and the second predetermined distance D2 areset to be generally equal to each other.

As discussed above, in the present embodiment, the shaft 35, the firstrod 71, the first valve lever 61, the second rod 72, and the secondvalve lever 62 form a link mechanism. When the output shaft 32 and theshaft 35 are axially moved by a drive force of the actuator 30, themotion of the output shaft 32 and the shaft 35 is transmitted to thefirst valve 17 and the second valve 18 through the link mechanism toopen or close the first valve 17 and the second valve 18.

Next, the operation of the valve drive apparatus 1 of the presentembodiment will be described with reference to FIGS. 4A to 6B.

As shown in FIG. 4A, in the state where the first valve 17 and thesecond valve 18 are both held in the valve closed state (the fullyclosed state), the first contact part 411 and the screw part 91 arespaced from each other. The drive amount of the output shaft 32, i.e.,the drive amount (also referred to as the amount of stroke) of theactuator 30 at this time will be denoted as a first drive amount K1. Atthis time, the urging force of the spring 81 is exerted against thesecond valve 18 through the second member 50, the second rod 72, and thesecond valve lever 62 to urge the second valve 18 in the valve closingdirection. In this way, the fully closed state of the second valve 18 ismaintained. Furthermore, at this time, the urging force of the spring 81is exerted against the first member 40 (the shaft 35, the output shaft32). Also, at this time, as shown in FIG. 4B, the exhaust gas issupplied to the turbine 13 through the first scroll 141.

Furthermore, in the valve closed state of the second valve 18, the firstmember 40 (the shaft 35, the output shaft 32) can be axially moved bythe urging force of the spring 81 from a position (see FIG. 4A), atwhich the first valve 17 is closed, to a position (see FIG. 5A), atwhich the first contact part 411 and the screw part 91 contact with eachother.

In the state shown in FIG. 4A, when the first member 40 (the shaft 35,the output shaft 32) is moved in a direction away from the actuator 30upon driving of the actuator 30 through the control operation of the ECU21, this motion of the first member 40 (the shaft 35, the output shaft32) is transmitted to the first valve 17 through the first rod 71 andthe first valve lever 61. Furthermore, at this time, the first contactpart 411 is moved toward the second contact part 511 (the gap formingportion 90).

When the first member 40 (the shaft 35, the output shaft 32) is furthermoved by the actuator 30 through the control operation of the ECU 21,the first contact part 411 contacts the screw part 91 of the gap formingportion 90 (see FIG. 5A). At this time, the drive amount of the actuator30 will be denoted as a second drive amount K2. At this time, the firstvalve 17 is held in the state where the first valve 17 is opened for apredetermined amount, and the second valve 18 is held in the valveclosed state (the fully closed state). Also, at this time, as shown inFIG. 5B, the exhaust gas is supplied to the turbine 13 through the firstscroll 141 and the second scroll 142.

When the first member 40 (the shaft 35, the output shaft 32) is furthermoved by the actuator 30 through the control operation of the ECU 21,the second member 50 is axially moved together with the first member 40in the state where the first contact part 411 and the screw part 91contact with each other. In this way, when the second member 50 is movedin a direction away from the actuator 30, this motion of the secondmember 50 is transmitted to the second valve 18 through the second rod72 and the second valve lever 62. Therefore, the second valve 18 isopened. At this time, the urging force of the spring 81 is canceledbetween the first member 40 and the second member 50 due to the contactbetween the first contact part 411 and the screw part 91. Therefore, theurging force of the spring 81 is not exerted against the output shaft 32of the actuator 30.

When the first member 40 (the shaft 35, the output shaft 32) is furthermoved by the actuator 30 through the control operation of the ECU 21,the second valve 18 is opened (increasing the opening degree) along withthe first valve 17 and is thereby placed in the state shown in FIG. 6A.

The actuator 30 can drive the first member 40 (the shaft 35, the outputshaft 32) until the first member 40 (the shaft 35, the output shaft 32)is placed in the position shown in FIG. 6A. The drive amount of theactuator 30 in the state shown in FIG. 6A will be denoted as a thirddrive amount K3. At this time, the opening degree of the first valve 17reaches it maximum opening degree, and the opening degree of the secondvalve 18 reaches its maximum opening degree. Also, at this time, asshown in FIG. 6B, the exhaust gas is supplied to the turbine 13 throughthe first scroll 141 and the second scroll 142, and the exhaust gas isalso conducted to the exhaust emission purifier 9 while bypassing theturbine 13.

As shown in FIG. 7A, in the present embodiment, when the drive amount ofthe actuator 30 is the second drive amount K2, the opening degree of thefirst valve 17 reaches a required opening degree. The required openingdegree is a minimum opening degree, at which a flow rate of the fluidpassing through the valve no longer changes.

Furthermore, when the drive amount of the actuator 30 is the third driveamount K3, the opening degree of the second valve 18 reaches therequired opening degree.

That is, in the present embodiment, a range from the first drive amountK1 to the second drive amount K2 is set as a substantial control rangeof the first valve 17. Furthermore, a range from the second drive amountK2 to the third drive amount K3 is set as a substantial control range ofthe second valve 18.

Furthermore, as shown in FIG. 7B, in the range (the control range of thefirst valve 17) from the first drive amount K1 to the second driveamount K2 of the actuator 30, the load, which is exerted against theactuator 30, is obtained by subtracting the valve driving force of theexhaust gas pulsation (exerted in the valve opening direction) from thegenerated torque of the spring 81 (exerted in the valve closingdirection). In the range from the second drive amount K2 to the thirddrive amount K3, the load, which is exerted against the actuator 30, isonly the valve driving force of the exhaust gas pulsation (exerted inthe valve opening direction).

As discussed above, in the present embodiment, when the first valve 17is in the fully closed state, the predetermined gap is formed betweenthe first member 40 and the second member 50 (the gap forming portion90). In this way, the second valve 18 can be held in the valve closedstate by urging the second valve 18 with the spring 81 until the firstvalve 17 is opened to the predetermined opening degree or larger. Thus,the first valve 17 (the change valve) can be driven within thepredetermined range while the second valve 18 (the waste gate valve) isheld in the fully closed state with the urging force of the spring 81.When the first valve 17 is opened to the predetermined opening degree orlarger, the first member 40 and the gap forming portion 90 (the screwpart 91) contact with each other, and the second valve 18 is openedsynchronously with the first valve 17 through the second valve lever 62,the second rod 72, the second member 50, the first member 40, the shaft35, the first rod 71, and the first valve lever 61.

As discussed above, according to the present embodiment, the linkmechanism is formed with the fewer number of the constituent members,and the two valves (the first valve 17 and the second valve 18) can bedriven by the single actuator 30. Therefore, the costs of theconstituent members of the valve drive apparatus 1 and the manufacturingcosts of the valve drive apparatus 1 can be reduced.

Furthermore, in the present embodiment, in the closed state of thesecond valve 18, when the first valve 17 is driven, the urging force ofthe spring 81 is exerted against the output shaft 32 of the actuator 30through the first member 40. At this time, the load of the actuator 30becomes large. In contrast, when the second valve 18 is opened, i.e.,when the second valve 18 is driven together with the first valve 17, theurging force of the spring 81 is canceled between the first member 40and the second member 50 through contact between the first member 40 andthe gap forming portion 90 (the screw part 91). Therefore, the urgingforce of the spring 81 is not exerted against the output shaft 32 of theactuator 30. Therefore, in the case where the second valve 18 is mainlyopened as the operation of the engine 2, the load of the actuator 30 isreduced, and thereby the stress on the actuator 30 can be reduced.

FIG. 8 is a diagram showing a relationship between the rotational speedof the engine 2 and a brake mean effective pressure (BMEP) or thetorque. As shown in FIG. 8, the operational range of the engine 2 issubstantially in the valve opening control range of the second valve 18.Therefore, in the present embodiment, the stress of the actuator 30 canbe reduced substantially in the entire operational range of the engine2. Therefore, the lifetime of the actuator 30 and its peripheral memberscan be lengthened. Furthermore, in the present embodiment, the actuator30 is the electric actuator. Therefore, the electric power consumptioncan be reduced.

Also, in the present embodiment, the spring 81 is made of the resilientmember, which has the predetermined modulus of elasticity. Furthermore,the one end part of the spring 81 is engaged with the first engagingpart 412 of the first member 40, and the other end part of the spring 81is engaged with the second engaging part 531 of the second member 50. Inthis way, the first valve 17 can be driven within the predeterminedrange while maintaining the fully closed state of the second valve 18with the urging force of the spring 81. The actuator 30 is installed tothe compressor housing 12. Therefore, it is possible to limit theincreasing of the temperature of the spring 81 to the high temperaturewith the heat of the exhaust gas. Thus, the spring 81 can be made of thelow cost member, which has the relatively low heat resistance.

Furthermore, in the present embodiment, the gap forming portion 90 isformed in and projects from the second contact part 511 toward the firstcontact part 411. The gap forming portion 90 forms the predetermined gapbetween the first contact part 411 and the second contact part 511 whenthe gap forming portion 90 contacts the first contact part 411. The gapforming portion 90 (the screw part 91) is formed such that the amount ofprojection of the gap forming portion 90 from the second contact part511 is variable (adjustable). In the present embodiment, the range,which is from the start of the valve opening of the first valve 17 tothe start of the valve opening of the second valve 18, is determined bythe gap between the first contact part 411 and the second contact part511. In the present embodiment, the gap between the first contact part411 and the second contact part 511 can be adjusted with the gap formingportion 90. Therefore, by adjusting the variations in the positionalrelationship between the first member 40 and the second member 50 andthe variations in the urging force of the spring 81, the control range(the operational range) of the first valve 17 can be accuratelydetermined. Thereby, the tolerances of the components can be increased,and the manufacturing costs can be reduced.

Second Embodiment

FIG. 9 shows a valve drive apparatus according to a second embodiment ofthe present disclosure. In the second embodiment, the structures of thefirst member, the second member and the urging device are different fromthose of the first embodiment.

In the second embodiment, the first contact part 411, which isconfigured into an annular form, is formed along an outer peripheraledge part of the other side surface of the main body 41 of the firstmember 40. Furthermore, the first engaging part 412 is formed in acenter part of the other side surface of the main body 41.

The second member 50 does not include the extension 53, which isdiscussed in the first embodiment. A second contact part 521 is formedin the end part of the tubular portion 52 of the second member 50, whichis opposite from the main body 51. The second contact part 521 cancontact the first contact part 411. A second engaging part 513 is formedin a center part of the one side surface of the main body 51 of thesecond member 50.

In the present embodiment, the spring 81 is placed between the main body51 and the first member 40 such that the spring 81 is received in theinside of the tubular portion 52 of the second member 50. The spring 81is engaged with the first engaging part 412 of the first member 40 atone end part of the spring 81 and is engaged with the second engagingpart 513 of the second member 50 at the other end part of the spring 81.In the present embodiment, the spring 81 has a predetermined modulus ofelasticity and has an axially contracting force. Specifically, thespring 81 urges the first member 40 and the second member 50 to urge thefirst contact part 411 and the second contact part 521 toward eachother.

In the present embodiment, the gap forming portion 90 is provided to thefirst contact part 411 of the main body 41. The amount of projection ofthe screw part 91 from the first contact part 411 toward the secondcontact part 521 can be adjusted. In this way, it is possible to adjusta size of the gap between the first contact part 411 of the first member40 and the second contact part 521 of the second member 50.

Thus, even in the second embodiment, the first valve 17 (the changevalve) can be driven within the predetermined range while the secondvalve 18 (the waste gate valve) is held in the fully closed state withthe urging force of the spring 81.

Third Embodiment

FIG. 10 shows a valve drive apparatus according to a third embodiment ofthe present disclosure. In the third embodiment, the structures of thefirst member, the second member and the urging device are different fromthose of the first embodiment.

In the third embodiment, the first member 40 further includes a mainbody 42. The main body 42 is formed to radially outwardly project froman axial intermediate part of the shaft 35. A first contact part 421 isformed in a main body 41 side of the main body 42. Here, the main body41 serves as an upper member of the present disclosure, and the mainbody 42 serves as a lower member of the present disclosure.

The second member 50 includes a main body 54. The main body 54 isconfigured into a generally cylindrical tubular form. The main body 54is placed between the main body 41 and the main body 42 such that themain body 54 can axially reciprocate (i.e., axially reciprocatable) in astate where the shaft 35 is received through the main body 54. A secondcontact part 541 is formed in a main body 42 side of the main body 54. Asecond engaging part 542 is formed in a main body 41 side of the mainbody 54. Furthermore, a shaft part 543 is formed in the main body 54.The shaft part 543 is configured into a generally cylindrical tubularform and extends in a radial direction of the main body 54. The otherend part of the second rod 72 is rotatably connected to the shaft part543.

In the present embodiment, the spring 81 is placed on the radially outerside of the shaft 35 and is located between the main body 41 and themain body 42 of the first member 40. The spring 81 is engaged with thefirst engaging part 412 of the first member 40 at one end part of thespring 81 and is engaged with the second engaging part 542 of the secondmember 50 at the other end part of the spring 81. In the presentembodiment, the spring 81 has a predetermined modulus of elasticity andhas an axially expanding force. Specifically, the spring 81 urges thefirst member 40 and the second member 50 to urge the first contact part421 and the second contact part 541 toward each other.

In the present embodiment, the gap forming portion 90 is provided to thefirst contact part 421 of the main body 42. The amount of projection ofthe screw part 91 from the first contact part 421 toward the secondcontact part 541 can be adjusted. In this way, it is possible to adjusta size of the gap between the first contact part 421 of the first member40 and the second contact part 541 of the second member 50.

Thus, even in the third embodiment, the first valve 17 (the changevalve) can be driven within the predetermined range while the secondvalve 18 (the waste gate valve) is held in the fully closed state withthe urging force of the spring 81.

Fourth Embodiment

FIG. 11 shows a valve drive apparatus according to a fourth embodimentof the present disclosure. In the fourth embodiment, the structures ofthe actuator, the shaft, the first member, and the second member aredifferent from those of the first embodiment.

In the fourth embodiment, the shaft 35 is provided separately from theoutput shaft 32 of the actuator 30. One end part of the shaft 35 isfixed to the compressor housing 12.

The housing 31 of the actuator 30 is fixed to the compressor housing 12such that the output shaft 32 is generally perpendicular to the axis ofthe shaft 35. Furthermore, a shaft part 321, which is configured into agenerally cylindrical tubular form and extends in a radial direction ofthe output shaft 32, is formed in the distal end part of the outputshaft 32.

The first member 40 includes a main body 43, a tubular portion 44, andan extension 45.

The main body 43 is configured into a generally annular form. The mainbody 43 can axially reciprocate in a state where the shaft 35 isreceived through the main body 43. A first engaging part 431 is formedin one side surface of the main body 43. The tubular portion 44 isconfigured into a tubular form and extends from an outer peripheral edgepart of the main body 43. The extension 45 is configured into an annularform and radially inwardly extends from an opposite end part of thetubular portion 44, which is opposite from the main body 43. A firstcontact part 451 is formed in a surface of the extension 53, which islocated on a side where the main body 43 is placed. A shaft part 432 isformed in the main body 43. The shaft part 432 is configured into agenerally cylindrical tubular form and extends in a direction (radialdirection), which is parallel to a plane of the main body 43. The otherend part of the first rod 71 is rotatably connected to the shaft part432.

The second member 50 includes a main body 54. The structure of thesecond member 50 of the present embodiment is similar to the secondmember 50 of the third embodiment, and thereby the description of thesecond member 50 is omitted for the sake of simplicity.

In the present embodiment, the spring 81 is placed on the radially outerside of the shaft 35 and on the radially inner side of the tubularportion 44 and is located between the main body 43 and the main body 54.The spring 81 is engaged with the first engaging part 431 of the firstmember 40 at one end part of the spring 81 and is engaged with thesecond engaging part 542 of the second member 50 at the other end partof the spring 81. In the present embodiment, the spring 81 has apredetermined modulus of elasticity and has an axially expanding force.Specifically, the spring 81 urges the first member 40 and the secondmember 50 to urge the first contact part 451 and the second contact part541 toward each other.

In the present embodiment, the gap forming portion 90 is provided to thefirst contact part 451 of the extension 45. The amount of projection ofthe screw part 91 from the first contact part 451 toward the secondcontact part 541 can be adjusted. In this way, it is possible to adjusta size of the gap between the first contact part 451 of the first member40 and the second contact part 541 of the second member 50.

In the present embodiment, a third rod 73 is further provided. The thirdrod 73 is configured into a rod form. The third rod 73 is rotatablyconnected to the shaft part 321 of the output shaft 32 at one end partof the third rod 73 and is rotatably connected to the shaft part 432 ofthe first member 40 at the other end part of the third rod 73. With theabove construction, when the output shaft 32 is axially moved in theaxial direction thereof, the motion of the output shaft 32 istransmitted to the first valve 17 through the third rod 73, the firstrod 71, and the first valve lever 61 to open or close the first valve17.

As discussed above, in the present embodiment, the shaft 35 is providedseparately from the output shaft 32. The first member 40 and the secondmember 50 are movable relative to the shaft 35. The other end part ofthe first rod 71 is connected to the first member 40. The third rod 73,which connects between the output shaft 32 and the first member 40, isfurther provided. In this way, the moving direction of the shaft 35 andthe moving direction of the output shaft 32 can be made different fromeach other. Thereby, a degree of freedom with respect to the arrangementof the actuator 30 and the link mechanism can be improved.

Thus, even in the fourth embodiment, the first valve 17 (the changevalve) can be driven within the predetermined range while the secondvalve 18 (the waste gate valve) is held in the fully closed state withthe urging force of the spring 81.

Fifth Embodiment

FIG. 12 shows a valve drive apparatus according to a fifth embodiment ofthe present disclosure. In the fifth embodiment, the structure of thefirst member is different from that of the first embodiment.

In the fifth embodiment, the first member 40 further includes a tubularportion 46. The tubular portion 46 is configured into a generallycylindrical tubular form and extends from the outer peripheral edge partof the main body 41 toward the extension 53 of the second member 50.Specifically, the tubular portion 46 is coaxial with the shaft 35. Thetubular portion 46 is placed on the radially inner side of the tubularportion 52 of the second member 50 and on the radially outer side of thespring 81.

In the present embodiment, an outer wall of the tubular portion 46 ofthe first member 40 and an inner wall of the tubular portion 52 canslide relative to each other. Therefore, when the second member 50 ismoved relative to the first member 40, the orientation of the secondmember 50 is stable. In this way, the swing of the axis of the secondmember 50 relative to the shaft 35 can be limited, and thereby thelifetime of the corresponding members can be improved. Here, the tubularportion 46 serves as a first tubular portion of the present disclosure,and the tubular portion 52 serves as a second tubular portion of thepresent disclosure.

Sixth Embodiment

FIG. 13A shows a valve drive apparatus according to a sixth embodimentof the present disclosure. In the sixth embodiment, the structure of thevalve drive apparatus 1 is similar to that of the first embodiment.However, the structure of the supercharger, to which the valve driveapparatus 1 is installed, is different from the first embodiment.

In the sixth embodiment, the supercharger 22 includes a first flow path221, a second flow path 222, and a third flow path 223. The first flowpath 221 connects between the engine 2 and the first scroll 141. Thesecond flow path 222 connects between the first flow path 221 and thesecond scroll 142. Here, the first flow path 221 and the second flowpath 222 serve as an exhaust flow path of the present disclosure. Thethird flow path 223 connects between the first flow path 221 and theexhaust emission purifier 9 while bypassing the turbine 13. Here, thethird flow path 223 serves as a bypass flow path of the presentdisclosure.

In the present embodiment, the first valve 17 (the change valve) isplaced in the second flow path 222 such that the first valve 17 can openand close the second flow path 222. The second valve 18 (the waste gatevalve) is placed in the third flow path 223 such that the second valve18 can open and close the third flow path 223.

Even in the present embodiment, the advantages, which are similar tothose of the first embodiment, can be achieved.

Seventh Embodiment

FIG. 13B shows a valve drive apparatus according to a seventh embodimentof the present disclosure. In the seventh embodiment, the structure ofthe valve drive apparatus 1 is similar to that of the first embodiment.However, the structure of the supercharger, to which the valve driveapparatus 1 is installed, is different from the first embodiment.

In the seventh embodiment, the supercharger 23 includes a first flowpath 231, a second flow path 232, a third flow path 233, and a fourthflow path 234. The first flow path 231 connects between the engine 2 andthe first scroll 141. The second flow path 232 connects between thefirst flow path 231 and the second scroll 142. The third flow path 233connects between the second flow path 232 and the exhaust emissionpurifier 9 while bypassing the turbine 13. The fourth flow path 234connects between the first flow path 231 and the third flow path 233while bypassing the turbine 13. Here, the first flow path 231 and thesecond flow path 232 serve as an exhaust flow path of the presentdisclosure. Furthermore, the third flow path 233 and the fourth flowpath 234 serve as a bypass flow path of the present disclosure.

In the present embodiment, the first valve 17 (the change valve) isplaced in the second flow path 232 such that the first valve 17 can openand close the second flow path 232. The second valve 18 (the waste gatevalve) is placed in a connection between the third flow path 233 and thefourth flow path 234 such that the second valve 18 can open and closethe third flow path 233 and the fourth flow path 234.

Even in the present embodiment, the advantages, which are similar tothose of the first embodiment, can be achieved.

Eighth Embodiment

FIG. 14 shows a valve drive apparatus according to an eighth embodimentof the present disclosure. In the eighth embodiment, the structure ofthe valve drive apparatus 1 is similar to that of the first embodiment.However, the subject apparatus, to which the valve drive apparatus ofthe fourth embodiment is applied, differs from that of the firstembodiment.

In the eighth embodiment, the valve drive apparatus 1 is installed to asupercharger 24, which supercharges the intake air to the engine 2. Thesupercharger 24 includes a first compressor 251, a second compressor252, a first turbine 261, a second turbine 262, a first shaft 263, asecond shaft 264, the first valve 17 and the second valve 18.

The first compressor 251 and the second compressor 252 are placed in theintake passage 6, which guides the intake air to the engine 2.

The first turbine 261 and the second turbine 262 are placed in theexhaust passage 10, which conducts the exhaust gas outputted from theengine 2. The first turbine 261 is connected to the first compressor 251through the first shaft 263. In this way, the first turbine 261 canrotate the first compressor 251 when the exhaust gas is supplied to thefirst turbine 261 to rotate the same. Here, the first turbine 261 isused as, for example, a low speed (small flow rate) turbine.

Furthermore, the second turbine 262 is connected to the secondcompressor 252 through the second shaft 264. In this way, the secondturbine 262 can rotate the second compressor 252 when the exhaust gas issupplied to the second turbine 262 to rotate the same. Here, the secondturbine 262 is used as, for example, a high speed (large flow rate)turbine.

In the present embodiment, a first exhaust flow path 271 and a secondexhaust flow path 272 are formed in the exhaust passage 10. The firstexhaust flow path 271 guides the exhaust gas from the engine 2 to thefirst turbine 261. The second exhaust flow path 272 guides the exhaustgas from the engine 2 to the second turbine 262. Here, an opposite endpart of the second exhaust flow path 272, which is opposite from thesecond turbine 262, is connected to the first exhaust flow path 271.

Furthermore, a bypass flow path 273 connects between one side (upstreamside) of the first turbine 261 and the second turbine 262, at which theinternal combustion engine 2 is located, and an opposite side(downstream side) of the first turbine 261 and the second turbine 262,which is opposite from the internal combustion engine 2, in the exhaustpassage 10, while the bypass flow path 273 bypasses the first turbine261 and the second turbine 262.

The first valve 17 is placed in the second exhaust flow path 272 suchthat the first valve 17 can open and close the second exhaust flow path272 upon rotation of the first valve 17 about the axis of the firstvalve shaft 173. The second valve 18 is placed in the bypass flow path273 such that the second valve 18 can open and close the bypass flowpath 273 upon rotation of the second valve 18 about the axis of thesecond valve shaft 183.

In the valve closed state of the first valve 17, the exhaust gas isguided to the first turbine 261 through the first exhaust flow path 271to rotate the first turbine 261. In contrast, in the valve open state ofthe first valve 17, the exhaust gas is guided to the first turbine 261through the first exhaust flow path 271 to rotate the first turbine 261and is also guided to the second turbine 262 through the second exhaustflow path 272 to rotate the second turbine 262. As discussed above, thefirst valve 17 functions as the change valve and can control the amountof exhaust gas supplied to the two turbines (the first turbine 261 andthe second turbine 262). That is, in the present embodiment, thesupercharger 22 is a two-stage supercharger.

When the second valve 18 is in the valve open state, the portion of theexhaust gas in the exhaust passage 10 is conducted through the bypassflow path 273. Therefore, the rotational speed of the first turbine 261and the rotational speed of the second turbine 262 are reduced to causea reduction in the supercharging pressure. In this way, it is possibleto limit the excessive increase of the supercharging pressure. Asdiscussed above, the second valve 18 functions as the waste gate valveand controls the amount of exhaust gas, which bypasses the first turbine261 and the second turbine 262.

The valve drive apparatus 1 is installed to the supercharger 24 in sucha manner that the valve drive apparatus 1 can drive the first valve 17and the second valve 18. Specifically, in the present embodiment, thevalve drive apparatus 1 is applied to the two-stage supercharger (thesupercharger 24), which includes the waste gate valve. The valve driveapparatus 1 drives the first valve 17 and the second valve (the wastegate valve) 18 while the first valve 17 controls the amount of exhaustgas supplied to the two turbines (the first turbine 261 and the secondturbine 262), and the second valve 18 (the waste gate valve) controlsthe amount of exhaust gas, which bypasses the turbines (the firstturbine 261 and the second turbine 262).

The actuator 30, the shaft 35, the first member 40, the second member50, the first valve lever 61, the second valve lever 62, the first rod71, the second rod 72, and the spring 81 of the present embodiment arethe same as those of the first embodiment. Therefore, the first valve 17(the change valve) can be driven within the predetermined range by theactuator 30 while maintaining the fully closed state of the second valve18 (the waste gate valve) with the urging force of the spring 81. As aresult, the advantages, which are similar to those of the firstembodiment, can be achieved in the eighth embodiment.

Ninth Embodiment

FIGS. 15 to 19 show a valve drive apparatus according to a ninthembodiment of the present disclosure. The ninth embodiment is amodification of the first embodiment, and an actuator of the valve driveapparatus and its associated components are different from those of thefirst embodiment. In the following discussion, the components, which aresimilar to those of the first embodiment, are indicated by the samereference numerals and will not be described redundantly for the sake ofsimplicity.

As shown in FIG. 15, the valve drive apparatus 1 of the presentembodiment includes an actuator 730, a first drive lever 740, a seconddrive lever 750, a first valve lever 61, a second valve lever 62, afirst rod 65, a second rod 66, a first predetermined shape portion 771,a second predetermined shape portion 772, a spring (serving as an urgingdevice and a resilient member) 781, and a gap forming portion 90.

As shown in FIG. 16, the actuator 730 includes a housing 731, anelectric motor (hereinafter referred to as a motor) 734, a gear member736, an output shaft 737, and a rotational position sensor 738.

The housing 731 is made of, for example, metal and includes a tubularportion 732 and a cover portion 733. The tubular portion 732 isconfigured into a cup form. The cover portion 733 is configured into acup form and has an opening, which contacts an opening of the tubularportion 732.

The motor 734 is received in the tubular portion 732. The motor 734includes a stator and a rotor (not shown). A motor shaft 735 is placedin a rotational center of the rotor. When an electric power is suppliedto the motor 734, the rotor and the motor shaft 735 are rotated.

The gear member 736 is placed in the inside of the cover portion 733such that the gear member 736 is connected to the motor shaft 735. Oneend part of the output shaft 737 is connected to the gear member 736,and the other end part of the output shaft 737 is exposed to the outsideof the cover portion 733. An axis of the output shaft 737 is parallel toan axis of the motor shaft 735. The output shaft 737 is rotatablysupported by the cover portion 733.

A rotational speed of the rotation, which is outputted from the motor734 (the motor shaft 735), is reduced through the gear member 736, andthe rotation of the reduced rotational speed is outputted through theoutput shaft 737. The rotational position sensor 738 is provided in thegear member 736. The rotational position sensor 738 outputs a signal,which indicates a relative rotational position between the output shaft737 and the cover portion 733, to the ECU 21. In this way, the ECU 21can sense the rotational position of the output shaft 737. The ECU 21adjusts the electric power, which is supplied to the motor 734, based onthe signal of the rotational position sensor 738 and the otherinformation to control the rotation of the motor 734. Thereby, therotation of the output shaft 737 is controlled.

The actuator 730 is installed to the supercharger 3 such that thehousing 731 is fixed to the compressor housing 12.

The first drive lever 740 is made of, for example, metal and is placedon an opposite side of the cover portion 733, which is opposite from thetubular portion 732. The first drive lever 740 includes a main body 741,a projection 742, and a first drive lever shaft 743. The main body 741is configured into, for example, a generally circular disk plate formand is generally parallel to a bottom surface of the cover portion 733.As shown in FIG. 19, a hole is formed in a center of the main body 741,and the output shaft 737 is fitted into this hole. In this way, the mainbody 741 (the first drive lever 740) can rotate integrally with theoutput shaft 737. The projection 742 radially outwardly projects from anouter peripheral part of the main body 741.

The first drive lever shaft 743 is made of, for example, metal and isconfigured into a generally cylindrical tubular form. The first drivelever shaft 743 is placed on an opposite side of the projection 742,which is opposite from the main body 741. An axis of the first drivelever shaft 743 is parallel to the axis of the output shaft 737 and isplaced at a location that is spaced from the axis of the output shaft737 by a first predetermined distance D1 (see FIGS. 15 and 19).

The second drive lever 750 is made of, for example, metal and is placedon an opposite side of the first drive lever 740, which is opposite fromthe cover portion 733. The second drive lever 750 includes a main body751, an engaging part 752 and a second drive lever shaft 753. The mainbody 751 is configured into, for example, a generally circular diskplate form and is generally parallel to the main body 741 of the firstdrive lever 740. As shown in FIG. 19, a hole is formed in a center ofthe main body 751, and a bearing 754 is placed in this hole. The endpart of the output shaft 737 is fitted into the bearing 754. In thisway, the main body 751 (the second drive lever 750) can rotate relativeto the output shaft 737 and the first drive lever 740. The engaging part752 radially outwardly projects from an outer peripheral edge part ofthe main body 751 and extends toward the first drive lever 740.

The second drive lever shaft 753 is made of, for example, metal and isconfigured into a generally cylindrical tubular form. The second drivelever shaft 753 is placed at the outer peripheral edge part of the mainbody 751. An axis of the second drive lever shaft 753 is parallel to theaxis of the output shaft 737 and is placed at a location, which isspaced from the axis of the output shaft 737 by a second predetermineddistance D2 (see FIG. 15).

The first drive lever 740 and the second drive lever 750 are placed oneafter another in an axial direction of the output shaft 737.

As shown in FIG. 15, the first valve lever 61 includes a main body 611and a first valve lever shaft 612. The main body 611 is made of, forexample, metal and is configured into an elongated plate form. One endpart of the main body 611 is fixed to the first valve shaft 173. A platethickness direction of the main body 611 (i.e., a directionperpendicular to a plane of the main body 611) is generally parallel tothe axis of the first valve shaft 173. In this way, the main body 611(the first valve lever 61) can rotate integrally with the first valveshaft 173. Thus, when the main body 611 is rotated integrally with thefirst valve shaft 173, the first valve 17 is opened or closed.

The first valve lever shaft 612 is made of, for example, metal and isconfigured into a generally cylindrical tubular form. The first valvelever shaft 612 is placed at the other end part of the main body 611. Anaxis of the first valve lever shaft 612 is parallel to the axis of thefirst valve shaft 173 and is placed at a location, which is spaced fromthe axis of the first valve shaft 173 by a third predetermined distanceD3.

As shown in FIG. 15, the second valve lever 62 includes a main body 621and a second valve lever shaft 622. The main body 621 is made of, forexample, metal and is configured into an elongated plate form. One endpart of the main body 621 is fixed to the second valve shaft 183. Aplate thickness direction of the main body 621 (i.e., a directionperpendicular to a plane of the main body 621) is generally parallel tothe axis of the second valve shaft 183. In this way, the main body 621(the second valve lever 62) can rotate integrally with the second valveshaft 183. Thus, when the main body 621 is rotated integrally with thesecond valve shaft 183, the second valve 18 is opened or closed.

The second valve lever shaft 622 is made of, for example, metal and isconfigured into a generally cylindrical tubular form. The second valvelever shaft 622 is placed at the other end part of the main body 621. Anaxis of the second valve lever shaft 622 is parallel to the axis of thesecond valve shaft 183 and is placed at a location, which is spaced fromthe axis of the second valve shaft 183 by a fourth predetermineddistance D4.

The first rod 65 is made of, for example, metal and is configured into arod form. The first rod 65 is rotatably connected to the first drivelever shaft 743 at one end part of the first rod 65 and is rotatablyconnected to the first valve lever shaft 612 at the other end part ofthe first rod 65, which is opposite from the one end part of the firstrod 65.

The second rod 66 is made of, for example, metal and is configured intoa rod form. The second rod 66 is rotatably connected to the second drivelever shaft 753 at one end part of the second rod 66 and is rotatablyconnected to the second valve lever shaft 622 at the other end part ofthe second rod 66, which is opposite from the one end part of the secondrod 66.

The first predetermined shape portion 771 is formed integrally with themain body 741 such that the first predetermined shape portion 771radially outwardly projects from an outer peripheral edge part of themain body 741 of the first drive lever 740. The first predeterminedshape portion 771 is formed at a corresponding location of the firstdrive lever 740, which is spaced from the axis of the output shaft 737by a predetermined distance.

As shown in FIG. 19, in the present embodiment, a cross section of thefirst predetermined shape portion 771 is configured into an L-shape.That is, the first predetermined shape portion 771 is formed by bendinga member, which forms the main body 741. An engaging part 711 is formedin the first predetermined shape portion 771.

The second predetermined shape portion 772 is formed integrally with themain body 751 such that the second predetermined shape portion 772radially outwardly projects from an outer peripheral edge part of themain body 751 of the second drive lever 750. The second predeterminedshape portion 772 is formed at a corresponding location of the seconddrive lever 750, which is spaced from the axis of the output shaft 737by a predetermined distance.

The second predetermined shape portion 772 contacts the firstpredetermined shape portion 771 through relative rotation between thefirst drive lever 740 and the second drive lever 750.

The spring 781 is made of a resilient member that is made of, forexample, metal. The spring 781 is configured into a coil form. That is,as shown in FIG. 19, the spring 781 is a coil spring and is placedbetween the main body 741 of the first drive lever 740 and the main body751 of the second drive lever 750 such that the axis of the spring 781is generally parallel to the axis of the output shaft 737. The spring781 has one end part, which is engaged with the engaging part 711 of thefirst predetermined shape portion 771, and the other end part, which isengaged with the engaging part 752 of the second drive lever 750 (seeFIGS. 15, 16, and 20). The spring 781 has a predetermined modulus ofelasticity. Furthermore, the spring 781 urges the first drive lever 740and the second drive lever 750 to move the first predetermined shapeportion 771 and the second predetermined shape portion 772 toward eachother. In the present embodiment, a spacer 782, which is annular, isplaced on a radially inner side of the spring 781. In this way,collapsing of the spring 781 is limited.

The gap forming portion 90 is made of, for example, metal and is placedat the second predetermined shape portion 772. As shown in FIGS. 15 and20, the gap forming portion 90 includes a screw part 91 and a nut 92.The screw part 91 is configured into a generally cylindrical rod formand has a male thread in an outer peripheral wall of the screw part 91.The screw part 91 is threaded into a threaded hole, which is formed inthe second predetermined shape portion 772 and has a female threadformed in an inner peripheral wall of the threaded hole. When the screwpart 91 is threaded into the threaded hole of the second predeterminedshape portion 772, the screw part 91 projects from the secondpredetermined shape portion 772 by a predetermined amount toward thefirst predetermined shape portion 771. The amount of projection of thescrew part 91 from the second predetermined shape portion 772 toward thefirst predetermined shape portion 771 can be adjusted by adjusting theamount of insertion of the screw part 91 into the threaded hole of thesecond predetermined shape portion 772.

The nut 92 is configured into an annular form and has a female thread,which corresponds to the male thread of the screw part 91, in an innerperipheral wall of the nut 92. The nut 92 is threadably installed to thescrew part 91 from an end of the screw part 91, which is opposite fromthe first predetermined shape portion 771, such that the nut 92 contactsthe second predetermined shape portion 772. In this way, the screw part91 is non-displaceably held relative to the second predetermined shapeportion 772.

As shown in FIGS. 15 and 21A, in the state where the first valve 17 andthe second valve 18 are both held in the valve closed state (the fullyclosed state), the screw part 91 and the first predetermined shapeportion 771 are spaced from each other. In contrast, as shown in FIG.21B, in the state where the second valve 18 is held in the valve closedstate (the fully closed state), when the first valve 17 is opened for apredetermined amount, the screw part 91 and the first predeterminedshape portion 771 contact with each other. At this time, a predeterminedgap is formed between the first predetermined shape portion 771 and thesecond predetermined shape portion 772.

In the present embodiment, as shown in FIG. 15, the second drive lever750 and the second valve lever 62 are formed such that the secondpredetermined distance D2 is set to be smaller than the fourthpredetermined distance D4. That is, the second drive lever 750 and thesecond valve lever 62 are formed to satisfy the relationship of D2<D4.The first drive lever 740 and the first valve lever 61 are formed suchthat the first predetermined distance D1 and the third predetermineddistance D3 are set to be generally equal to each other. That is, thefirst drive lever 740 and the first valve lever 61 are formed to satisfythe relationship of D1≈D3.

As discussed above, in the present embodiment, the first drive lever740, the first rod 65, the first valve lever 61, the second drive lever750, the second rod 66, and the second valve lever 62 form a linkmechanism (four-bar linkage). When the first drive lever 740 and thesecond drive lever 750 are rotated through the operation of the actuator730, the rotation of the first drive lever 740 and the rotation of thesecond drive lever 750 are conducted to the first valve 17 and thesecond valve 18, respectively, to open or close the first valve 17 andthe second valve 18.

Next, the operation of the valve drive apparatus 1 of the presentembodiment will be described with reference to FIGS. 21A to 22B.

As shown in FIG. 21A, in the state where the first valve 17 and thesecond valve 18 are both held in the valve closed state (the fullyclosed state), the first predetermined shape portion 771 and the screwpart 91 are spaced from each other. The rotational angle of the outputshaft 737, i.e., the angle (rotational angle) of the actuator 730 inthis state is denoted as a first angle θ1. At this time, the urgingforce of the spring 781 is exerted against the second valve 18 throughthe second drive lever 750, the second rod 66, and the second valvelever 62 to urge the second valve 18 in the valve closing direction. Inthis way, the fully closed state of the second valve 18 is maintained.Furthermore, at this time, the urging force of the spring 781 is exertedagainst the first drive lever 740 (the output shaft 737).

Furthermore, in the valve closed state of the second valve 18, the firstdrive lever 740 can be rotated while receiving the urging force of thespring 781 through a corresponding rotational range that is from aposition, at which the first valve 17 is closed (see FIG. 21A), to aposition, at which the first predetermined shape portion 771 and thescrew part 91 contact with each other (see FIG. 21B).

In the state of FIG. 21A, when the ECU 21 drives the actuator 730 torotate the first drive lever 740 in the direction of opening the firstvalve 17, the first predetermined shape portion 771 is moved toward thesecond predetermined shape portion 772 (the gap forming portion 90).

Furthermore, when the ECU 21 drives the actuator 730 to further rotatethe first drive lever 740, the first predetermined shape portion 771contacts the screw part 91 of the gap forming portion 90 (see FIG. 21B).The angle of the actuator 730 in this state is denoted as a second angleθ2. At this time, the first valve 17 is held in the state where thefirst valve 17 is opened for a predetermined amount, and the secondvalve 18 is held in the valve closed state (the fully closed state).

Furthermore, when the ECU 21 drives the actuator 730 to further rotatethe first drive lever 740, the second drive lever 750 is rotatedtogether with the first drive lever 740 while the first predeterminedshape portion 771 and the screw part 91 contact with each other. In thisway, the second valve 18 is opened. At this time, the urging force ofthe spring 781 is canceled between the first drive lever 740 and thesecond drive lever 750 through contact between the first predeterminedshape portion 771 and the screw part 91. Therefore, the urging force ofthe spring 781 is not exerted against output shaft 737 of the actuator730.

Furthermore, when the ECU 21 drives the actuator 730 to further rotatethe first drive lever 740 (and the second drive lever 750), theprojection 742 of the first drive lever 740 and the first rod 65 arealigned and are placed to extend along a straight line. That is, a firststraight line L1, which is perpendicular to the axis of the output shaft737 and the axis of the first drive lever shaft 743, and a secondstraight line L2, which is perpendicular to the axis of the first drivelever shaft 743 and the axis of the first valve lever shaft 612, overlapwith each other along a common straight line (see FIG. 22A). The angleof the actuator 730 in this state is denoted as a third angle θ3. Inthis state, the opening degree of the first valve 17 is a maximumopening degree of the first valve 17 (see FIG. 23A).

When the ECU 21 drives the actuator 730 to further rotate the firstdrive lever 740 (and the second drive lever 750), the first valve 17 ismoved in the valve closing direction (reducing the opening degree of thefirst valve 17), and the second valve 18 is moved in the valve openingdirection (increasing the opening degree of the second valve 18).

The actuator 730 can drive the first drive lever 740 and the seconddrive lever 750 until each of the first drive lever 740 and the seconddrive lever 750 is placed in a corresponding position show in FIG. 22B.The angle of the actuator 730 in the state shown in FIG. 22B is denotedas a fourth angle θ4. In this state, the opening degree of the secondvalve 18 is a maximum opening degree of the second valve 18 (see FIG.23A).

As shown in FIG. 23A, in the present embodiment, when the angle of theactuator 730 is the second angle θ2, the opening degree of the firstvalve 17 is the required opening degree. The required opening degree isa minimum opening degree, at which a flow rate of the fluid passingthrough the valve no longer changes.

Furthermore, when the angle of the actuator 730 is a fifth angle θ5,which is between the second angle θ2 and the third angle θ3, the openingdegree of the second valve 18 becomes a required opening degree (seeFIG. 23A).

That is, in the present embodiment, a range from the first angle θ1 tothe second angle θ2 is set as a substantial control range of the firstvalve 17, and a range from the second angle θ2 to the fifth angle θ5 isset as a substantial control range of the second valve 18. Furthermore,a range from the fifth angle θ5 to the fourth angle θ4 is a controlrange for warming up of the catalyst of the exhaust emission purifier 9.

Furthermore, in the present embodiment, as shown in FIG. 23A, at thetime of holding the actuator 730 at the maximum opening degree thereof,i.e., the fourth angle θ4, the first valve 17 has an opening degree,which is equal to or larger than the required opening degree of thefirst valve 17.

Furthermore, as shown in FIG. 23B, in the range (the control range ofthe first valve 17) from the first angle θ1 to the second angle θ2 ofthe actuator 730, the load, which is exerted against the actuator 730,is obtained by subtracting the valve driving force of the exhaust gaspulsation (exerted in the valve opening direction) from the generatedtorque of the spring 781 (exerted in the valve closing direction). Inthe range from the second angle θ2 to the fourth angle θ4 of theactuator 730, the load, which is exerted against the actuator 730, isonly a valve driving force of the exhaust gas pulsation (exerted in thevalve opening direction).

Furthermore, in the present embodiment, when the angle of the actuator730 is the third angle θ3, the first straight line L1 and the secondstraight line L2 overlap with each other along the common straight line(see FIG. 22A), and the opening degree of the first valve 17 is themaximum opening degree. That is, the rotatable range of the first drivelever 740 includes the predetermined rotational position where the firststraight line L1, which is perpendicular to the axis of the output shaft737 and the axis of the first drive lever shaft 743, and the secondstraight line L2, which is perpendicular to the axis of the first drivelever shaft 743 and the axis of the first valve lever shaft 612, overlapwith each other along the common straight line.

Furthermore, in the present embodiment, as shown in FIG. 15, the seconddrive lever 750, the second rod 66, and the second valve lever 62 arearranged to satisfy all of the following conditions upon placement ofthe second valve 18 in the valve closed state (the fully closed state):an angle between a third straight line L3, which is perpendicular to theaxis of the output shaft 737 and the axis of the second drive levershaft 753, and a fourth straight line L4, which is perpendicular to theaxis of the second drive lever shaft 753 and the axis of the secondvalve lever shaft 622, is an acute angle; and an angle between a fifthstraight line L5, which is perpendicular to the axis of the second valvelever shaft 622 and the axis of the second valve shaft 183, and thefourth straight line L4 is a right angle. In this description, the term,“right angle” is not necessarily limited to the precise angle of 90degrees but may include a generally right angle (e.g., 89 degrees, 91degrees).

The first drive lever 740, the first rod 65, and the first valve lever61 are arranged to satisfy all of the following conditions uponplacement of the first valve 17 in the valve closed state (the fullyclosed state) shown in FIG. 15: an angle between the first straight lineL1 and the second straight line L2 is an obtuse angle; and an anglebetween a sixth straight line L6, which is perpendicular to the axis ofthe first valve lever shaft 612 and the axis of the first valve shaft173, and the second straight line L2 is an obtuse angle.

As discussed above, in the present embodiment, when the first valve 17is in the fully closed state, the predetermined gap is formed betweenthe first predetermined shape portion 771 and the second predeterminedshape portion 772 (the gap forming portion 90). In this way, the secondvalve 18 can be held in the valve closed state by urging the secondvalve 18 with the spring 781 until the first valve 17 is opened to thepredetermined opening degree or larger. Thus, the first valve 17 (thechange valve) can be driven within the predetermined range while thesecond valve 18 (the waste gate valve) is held in the fully closed statewith the urging force of the spring 781. When the first valve 17 isopened to the predetermined opening degree or larger, the firstpredetermined shape portion 771 and the gap forming portion 90 (thescrew part 91) contact with each other, and the second valve 18 isopened synchronously with the first valve 17 through the second valvelever 62, the second rod 66, the second drive lever 750, the first drivelever 740, the first rod 65, and the first valve lever 61.

As discussed above, according to the present embodiment, the linkmechanism is formed with the fewer number of the constituent members,and the two valves (the first valve 17 and the second valve 18) can bedriven by the single actuator 730. Therefore, the costs of theconstituent members of the valve drive apparatus 1 and the manufacturingcosts of the valve drive apparatus 1 can be reduced.

Furthermore, in the present embodiment, the distance between the outputshaft 737 and the first drive lever shaft 743, the distance between theoutput shaft 737 and the second drive lever shaft 753, the distancebetween the first valve shaft 173 and the first valve lever shaft 612,and the distance between the second valve shaft 183 and the second valvelever shaft 622, i.e., the first to fourth distances D1-D4 areappropriately set to enable the adjustment of the transmissionefficiency of the drive force of the actuator 730 to the first valve 17and the second valve 18. Therefore, the drive force of the actuator 730can be efficiently transmitted to the first valve 17 and the secondvalve 18.

Furthermore, in the present embodiment, in the closed state of thesecond valve 18, when the first valve 17 is driven, the urging force ofthe spring 781 is exerted against the output shaft 737 of the actuator730 through the first drive lever 740. At this time, the load of theactuator 730 becomes large. In contrast, when the second valve 18 isopened, i.e., when the second valve 18 is driven together with the firstvalve 17, the urging force of the spring 781 is canceled between thefirst drive lever 740 and the second drive lever 750 through contactbetween the first predetermined shape portion 771 and the gap formingportion 90 (the screw part 91). Therefore, the urging force of thespring 781 is not exerted against the output shaft 737 of the actuator730. Thus, in the case where the second valve 18 is mainly opened as theoperation of the engine 2, the load of the actuator 730 is reduced, andthereby the stress on the actuator 730 can be reduced.

The relationship between the rotational speed of the engine 2 and theBMEP or the torque of the present embodiment is similar to the onediscussed with reference to FIG. 8 in the first embodiment. That is, theoperational range of the engine 2 is substantially in the valve openingcontrol range of the second valve 18. Therefore, even in the presentembodiment, the stress of the actuator 730 can be reduced substantiallyin the entire operational range of the engine 2. Therefore, the lifetimeof the actuator 730 and its peripheral members can be lengthened.Furthermore, in the present embodiment, the actuator 730 is the electricactuator. Therefore, the electric power consumption can be reduced.

Also, in the present embodiment, the spring 781 is made of the resilientmember, which has the predetermined modulus of elasticity. Furthermore,the one end part of the spring 781 is engaged with the engaging part 711of the first predetermined shape portion 771, and the other end part ofthe spring 781 is engaged with the engaging part 752 of the second drivelever 750. In this way, the first valve 17 can be driven within thepredetermined range while maintaining the fully closed state of thesecond valve 18 with the urging force of the spring 781. The actuator730 is installed to the compressor housing 12. Therefore, it is possibleto limit the increasing of the temperature of the spring 781 to the hightemperature with the heat of the exhaust gas. Thus, the spring 781 canbe made of the low cost member, which has the relatively low heatresistance.

Furthermore, in the preset embodiment, the first drive lever 740 and thefirst valve lever 61 are formed such that the first predetermineddistance D1 and the third predetermined distance D3 are generally equalto each other. In addition, the first drive lever 740, the first rod 65,and the first valve lever 61 are arranged to satisfy all of thefollowing conditions upon placement of the first valve 17 in the valveclosed state (the fully closed state): the angle between the firststraight line L1 and the second straight line L2 is the obtuse angle;and the angle between the sixth straight line L6 and the second straightline L2 is the obtuse angle. Therefore, the rotatable range of the firstdrive lever 740 includes the predetermined rotational position where thefirst straight line L1 and the second straight line L2 overlap with eachother along the common straight line. Thus, when the actuator 730 isrotated in the valve opening direction of the second valve 18, theopening degree of the first valve 17 is reduced after the reaching ofthe maximum opening degree (the third angle θ3). In this way, themaximum opening degree (the upper limit) of the first valve 17 can beadjusted, and the receiving space (the dead volume) of the first valve17 in the turbine housing 14 can be reduced or minimized. As a result,it is possible to reduce the size of the turbine housing 14, and it isalso possible to limit the increase in the pressure loss and theincrease in the heat mass caused by the increase in the dead volume.

Furthermore, in the present embodiment, the second drive lever 750 andthe second valve lever 62 are formed such that the second predetermineddistance D2 is set to be smaller than the fourth predetermined distanceD4. In this way, the torque of the output shaft 737 (the second drivelever 750) can be amplified and can be transmitted to the second valvelever 62 (the second valve 18). Therefore, the drive force of theactuator 730 can be efficiently transmitted to the second valve 18.

Furthermore, in the present embodiment, the second drive lever 750, thesecond rod 66, and the second valve lever 62 are arranged to satisfy allof the following conditions upon placement of the second valve 18 in thevalve closed state (the fully closed state): the angle between the thirdstraight line L3 and the fourth straight line L4 is the acute angle; andthe angle between the fifth straight line L5 and the fourth straightline L4 is the right angle. In this way, the torque of the output shaft737 (the second drive lever 750) can be amplified and can be efficientlytransmitted to the second valve lever 62 (the second valve 18).

Furthermore, in the present embodiment, the gap forming portion 90 isformed in and projects from the second predetermined shape portion 772toward the first predetermined shape portion 771. The gap formingportion 90 forms the predetermined gap between the first predeterminedshape portion 771 and the second predetermined shape portion 772 whenthe gap forming portion 90 contacts the first predetermined shapeportion 771. The gap forming portion 90 (the screw part 91) is formedsuch that the amount of projection of the gap forming portion 90 fromthe second predetermined shape portion 772 is variable (adjustable). Inthe present embodiment, the range, which is from the start of the valveopening of the first valve 17 to the start of the valve opening of thesecond valve 18, is determined by the gap between the firstpredetermined shape portion 771 and the second predetermined shapeportion 772. In the present embodiment, the gap between the firstpredetermined shape portion 771 and the second predetermined shapeportion 772 can be adjusted by the gap forming portion 90. Therefore, byadjusting the variations in the positional relationship between thefirst drive lever 740 and the second drive lever 750 and the variationsin the torque of the spring 781, the control range (the operationalrange) of the first valve 17 can be accurately determined. Thereby, thetolerances of the components can be increased, and the manufacturingcosts can be reduced.

Furthermore, in the preset embodiment, the first drive lever 740 and thesecond drive lever 750 are placed one after another in the axialdirection of the output shaft 737. In addition, the first predeterminedshape portion 771 is formed by bending the member, which forms the firstdrive lever 740 (the main body 741). In this way, the first drive lever740 and the first predetermined shape portion 771 can be formed from thelow cost member (e.g., a press forming material, which is processedthrough a press forming process).

Tenth Embodiment

FIG. 24 shows a valve drive apparatus according to a tenth embodiment ofthe present disclosure. In the tenth embodiment, the arrangement of thefirst drive lever, the first rod, the first valve lever, the seconddrive lever, the second rod, and the second valve lever as well as therotational directions of the second valve shaft at the valve openingtime and the valve closing time of the second valve are different fromthose of the ninth embodiment.

FIG. 24 shows the valve drive apparatus in the state where the firstvalve 17 and the second valve 18 are both in the fully closed state. Inthe tenth embodiment, a seventh straight line L7 is perpendicular to theaxis of the output shaft 737 and the axis of the second valve levershaft 622, and the second drive lever shaft 753 is provided to the mainbody 751 of the second drive lever 750 on an opposite side of theseventh straight line L7, which is opposite from the first drive levershaft 743. In the ninth embodiment, the second drive lever shaft 753 isprovided to the main body 751 of the second drive lever 750 on the otherside of the seventh straight line L7 where the first drive lever shaft743 is located (see FIG. 15). Furthermore, in the tenth embodiment, thesecond drive lever 750, the second rod 66, and the second valve lever 62are arranged to satisfy the following condition upon placement of thesecond valve 18 in the fully closed state: an angle between the thirdstraight line L3 and the fourth straight line L4 is an obtuse angle.

In the tenth embodiment, the first drive lever 740, the first rod 65,the first valve lever 61, the second drive lever 750, the second rod 66,and the second valve lever 62 are arranged to satisfy the followingcondition upon rotation of the output shaft 737 in one rotationaldirection or the other rotational direction: the first valve shaft 173and the second valve shaft 183 are rotated in different rotationaldirections, respectively, so that the first valve 17 and the secondvalve 18 are opened or closed.

For example, when the output shaft 737 is rotated in the one rotationaldirection, i.e., a direction X0 (a counterclockwise direction in FIG.24), the first valve shaft 173 is rotated in a direction Y1 (a clockwisedirection in FIG. 24), so that the first valve 17 is opened. At thistime, the first rod 65 is axially compressed by the first drive levershaft 743 and the first valve lever shaft 612. When the output shaft 737is further rotated in the direction X0, the first predetermined shapeportion 771 and the screw part 91 contact with each other. Thereafter,when the output shaft 737 is further rotated in the direction X0, thesecond valve shaft 183 is rotated in a direction X2 (thecounterclockwise direction in FIG. 24). Thereby, the second valve 18 isopened. At this time, the second rod 66 is axially pulled by the seconddrive lever shaft 753 and the second valve lever shaft 622.

In the state where the first valve 17 and the second valve 18 areopened, when the output shaft 737 is rotated in the other rotationaldirection, i.e., a direction Y0 (the clockwise direction in FIG. 24),the first valve shaft 173 is rotated in a direction X1 (thecounterclockwise direction). Thereby, the first valve 17 is closed. Atthis time, the first rod 65 is axially pulled by the first drive levershaft 743 and the first valve lever shaft 612. Furthermore, at thistime, the second valve 18 is rotated in a direction Y2 (the clockwisedirection in FIG. 24), so that the second valve 18 is closed. At thistime, the second rod 66 is axially compressed by the second drive levershaft 753 and the second valve lever shaft 622.

As discussed above, in the present embodiment, the first drive lever740, the first rod 65, the first valve lever 61, the second drive lever750, the second rod 66, and the second valve lever 62 are arranged tosatisfy the following condition upon rotation of the output shaft 737 inthe one rotational direction (the direction X0 in FIG. 24) or the otherrotational direction (the direction Y0 in FIG. 24): the first valveshaft 173 and the second valve shaft 183 are rotated in the differentrotational directions (the clockwise direction or the counterclockwisedirection), respectively, so that the first valve 17 and the secondvalve 18 are opened or closed. That is, even in the case where the valveopening direction and the valve closing direction of the first valve 17are opposite from the valve opening direction and the valve closingdirection, respectively, of the second valve 18, the first valve 17 andthe second valve 18 can be opened or closed by rotating the output shaft737 of the actuator 730 in the one rotational direction or the otherrotational direction. Therefore, a design freedom of the turbine housing14, to which the first valve 17 and the second valve 18 are provided, isincreased, and thereby the installability of the valve drive apparatus 1in the vehicle can be improved.

Furthermore, in the present embodiment, at the time of opening the firstvalve 17, the first rod 65 is axially compressed by the first drivelever shaft 743 and the first valve lever shaft 612. At the time ofclosing the first valve 17, the first rod 65 is axially pulled by thefirst drive lever shaft 743 and the first valve lever shaft 612. Also,at the time of opening the second valve 18, the second rod 66 is axiallypulled by the second drive lever shaft 753 and the second valve levershaft 622. At the time of closing the second valve 18, the second rod 66is axially compressed by the second drive lever shaft 753 and the secondvalve lever shaft 622. As discussed above, in the present embodiment, atthe time of closing the first valve 17, the first rod 65 is axiallypulled by the first drive lever shaft 743 and the first valve levershaft 612. Therefore, even when a required load for fully closing thefirst valve 17 is set to a high value, damage of the first rod 65 can belimited. That is, the present embodiment is suitable for the case wherethe permissible amount of leakage of the first valve 17 is small, andthe required load for fully closing the first valve 17 can be set to thehigh value without inducing the damage of the first rod 65.

In the present embodiment, when the second valve 18 is closed, thesecond rod 66 is axially compressed by the second drive lever shaft 753and the second valve lever shaft 622. Therefore, when a required loadfor fully closing the second valve 18 is set to a high value, the secondrod 66 may possibly be collapsed. Thus, in the present embodiment, it isdesirable that the required load for fully closing the second valve 18is set to a small value.

Furthermore, in the embodiment, the second drive lever 750, the secondrod 66, and the second valve lever 62 are arranged to satisfy thefollowing condition upon placement of the second valve 18 in the fullyclosed state: an angle between the third straight line L3 and the fourthstraight line L4 is the obtuse angle. When the second valve 18 isrotated from the fully closed state in the valve opening direction (thedirection X2), the output shaft 737 is rotated such that the anglebetween the third straight line L3 and the fourth straight line L4 ischanged in the order of the right angle and the acute angle. Therefore,at the time of opening the second valve 18, the torque of the outputshaft 737 can be efficiently transmitted to the second valve 18.

Furthermore, in the present embodiment, the second drive lever 750, thesecond rod 66, and the second valve lever 62 are arranged to satisfy allof the following conditions upon placement of the second valve 18 in thevalve closed state (the fully closed state): the angle between the thirdstraight line L3 and the fourth straight line L4 is the obtuse angle;and the angle between the fifth straight line L5 and the fourth straightline L4 is the right angle. In this way, the torque of the output shaft737 (the second drive lever 750) can be amplified and can be transmittedto the second valve lever 62 (the second valve 18).

Eleventh Embodiment

FIG. 25 shows a valve drive apparatus according to an eleventhembodiment of the present disclosure. In the eleventh embodiment, thearrangement of the second drive lever, the second rod, and the secondvalve lever, the rotational directions of the first valve shaft at thevalve opening time and the valve closing time of the first valve, therotational directions of the second valve shaft at the valve openingtime and the valve closing time of the second valve, and the rotationaldirections of the output shaft at the valve opening time and the valveclosing time of the first valve and the second valve are different fromthose of the tenth embodiment.

FIG. 25 shows the valve drive apparatus in the state where the firstvalve 17 and the second valve 18 are both in the fully closed state. Inthe eleventh embodiment, the second drive lever shaft 753 is provided tothe main body 751 of the second drive lever 750 on the side of theseventh straight line L7, which is opposite from the first drive levershaft 743. Furthermore, in the eleventh embodiment, the second drivelever 750, the second rod 66, and the second valve lever 62 are arrangedto satisfy the following condition upon placement of the second valve 18in the fully closed state: an angle between the third straight line L3and the fourth straight line L4 is an acute angle.

Furthermore, in the eleventh embodiment, as shown in FIG. 25, thearrangement of the engaging part 752, the first predetermined shapeportion 771, the second predetermined shape portion 772, the spring 781,and the gap forming portion 90 is different from that of the tenthembodiment.

In the eleventh embodiment, the first drive lever 740, the first rod 65,the first valve lever 61, the second drive lever 750, the second rod 66,and the second valve lever 62 are arranged to satisfy the followingcondition upon rotation of the output shaft 737 in the one rotationaldirection or the other rotational direction: the first valve shaft 173and the second valve shaft 183 are rotated in the different rotationaldirections, respectively, so that the first valve 17 and the secondvalve 18 are opened or closed.

For example, when the output shaft 737 is rotated in the otherrotational direction, i.e., the direction Y0 (the clockwise direction inFIG. 25), the first valve shaft 173 is rotated in the direction X1 (thecounterclockwise direction in FIG. 25), so that the first valve 17 isopened. At this time, the first rod 65 is axially pulled by the firstdrive lever shaft 743 and the first valve lever shaft 612. When theoutput shaft 737 is further rotated in the direction Y0, the firstpredetermined shape portion 771 and the screw part 91 contact with eachother. Thereafter, when the output shaft 737 is further rotated in thedirection Y0, the second valve shaft 183 is rotated in the direction Y2(the clockwise direction in FIG. 25). Thereby, the second valve 18 isopened. At this time, the second rod 66 is axially compressed by thesecond drive lever shaft 753 and the second valve lever shaft 622.

In the state where the first valve 17 and the second valve 18 areopened, when the output shaft 737 is rotated in the one rotationaldirection, i.e., the direction X0 (the counterclockwise direction inFIG. 25), the first valve shaft 173 is rotated in the direction Y1 (theclockwise direction). Thereby, the first valve 17 is closed. At thistime, the first rod 65 is axially compressed by the first drive levershaft 743 and the first valve lever shaft 612. Furthermore, at thistime, the second valve 18 is rotated in the direction X2 (thecounterclockwise direction in FIG. 25), so that the second valve 18 isclosed. At this time, the second rod 66 is axially pulled by the seconddrive lever shaft 753 and the second valve lever shaft 622.

As discussed above, in the present embodiment, the first drive lever740, the first rod 65, the first valve lever 61, the second drive lever750, the second rod 66, and the second valve lever 62 are arranged tosatisfy the following condition upon rotation of the output shaft 737 inthe other rotational direction (the direction Y0 in FIG. 25) or the onerotational direction (the direction X0 in FIG. 25): the first valveshaft 173 and the second valve shaft 183 are rotated in the differentrotational directions (the counterclockwise direction or the clockwisedirection), respectively, so that the first valve 17 and the secondvalve 18 are opened or closed. That is, even in the case where the valveopening direction and the valve closing direction of the first valve 17are opposite from the valve opening direction and the valve closingdirection, respectively, of the second valve 18, the first valve 17 andthe second valve 18 can be opened or closed by rotating the output shaft737 of the actuator 730 in the other rotational direction or the onerotational direction. Therefore, similar to the tenth embodiment, thedesign freedom of the turbine housing 14, to which the first valve 17and the second valve 18 are provided, is increased, and thereby theinstallability of the valve drive apparatus 1 in the vehicle can beimproved.

Furthermore, in the present embodiment, at the time of opening the firstvalve 17, the first rod 65 is axially pulled by the first drive levershaft 743 and the first valve lever shaft 612. At the time of closingthe first valve 17, the first rod 65 is axially compressed by the firstdrive lever shaft 743 and the first valve lever shaft 612. Also, at thetime of opening the second valve 18, the second rod 66 is axiallycompressed by the second drive lever shaft 753 and the second valvelever shaft 622. At the time of closing the second valve 18, the secondrod 66 is axially pulled by the second drive lever shaft 753 and thesecond valve lever shaft 622. As discussed above, in the presentembodiment, at the time of closing the second valve 18, the second rod66 is axially pulled by the second drive lever shaft 753 and the secondvalve lever shaft 622. Therefore, even when the required load for fullyclosing the second valve 18 is set to the high value, damage of thesecond rod 66 can be limited. That is, the present embodiment issuitable for the case where the permissible amount of leakage of thesecond valve 18 is small, and the required load for fully closing thesecond valve 18 can be set to the high value without inducing the damageof the second rod 66.

In the present embodiment, when the first valve 17 is closed, the firstrod 65 is axially compressed by the first drive lever shaft 743 and thefirst valve lever shaft 612. Therefore, when a required load for fullyclosing the first valve 17 is set to a high value, the first rod 65 maypossibly be collapsed. Thus, in the present embodiment, it is desirablethat the required load for fully closing the first valve 17 is set to asmall value.

Furthermore, in the present embodiment, the second drive lever 750, thesecond rod 66, and the second valve lever 62 are arranged to satisfy thefollowing condition upon placement of the second valve 18 in the fullyclosed state: an angle between the third straight line L3 and the fourthstraight line L4 is an acute angle. When the second valve 18 is rotatedfrom the fully closed state in the valve opening direction (thedirection Y2), the output shaft 737 is rotated such that the anglebetween the third straight line L3 and the fourth straight line L4 ischanged in the order of the right angle and the obtuse angle. Therefore,at the time of opening the second valve 18, the torque of the outputshaft 737 can be efficiently transmitted to the second valve 18.

Now, modifications of the above embodiments will be described.

In a modification of the first to eleventh embodiments, the first valvemay be used as a variable nozzle, which controls the amount of exhaustgas supplied to the turbine, i.e., as a variable nozzle of a variabledisplacement supercharger. In such a case, the first valve (the variablenozzle) can be driven within the predetermined range by the actuatorwhile maintaining the fully closed state of the second valve (the wastegate valve) with the urging force of the urging device.

In the first to eighth embodiments, the corresponding member (the firstmember, the second member) includes the tubular portion. In amodification of the above embodiments, the tubular portion is notnecessarily continuous in the circumferential direction and may beconfigured such that a circumferential portion of the tubular portion iscut to provide a circumferentially discontinuous tubular portion havinga C-shape cross section.

In the first to eleventh embodiments, the urging device is not limitedto the metal coil spring. That is, in a modification of the first toeleventh embodiments, the urging device may be made of a resilientmember, which is made of a material different from that of the metalcoil spring and has a shape different from that of the metal coilspring.

Furthermore, in a modification of the first to eighth embodiments, thegap forming portion may be formed in any one of the first contact partand the second contact part. Furthermore, the valve drive apparatus maynot have the gap forming portion. In such a case, the first contact partand the second contact part can contact with teach other, and the gapbetween the first contact part and the second contact part cannot beadjusted. However, the first valve can be driven within a predeterminedrange by the actuator while the second valve is held in the fully closedstate with the urging force of the urging device.

Furthermore, in the first to eighth embodiments, the actuator is notlimited to the electric actuator as long as the output shaft of theactuator is movable in the axial direction. For instance, the actuatormay be an actuator, which is driven by a pneumatic pressure, a hydraulicpressure or any other drive fore.

In a modification of the ninth to eleventh embodiments, the rotationalrange of the first drive lever may not include the rotational positionwhere the first straight line and the second straight line overlap witheach other along the common straight line.

Furthermore, in another modification of the ninth to eleventhembodiments, the second drive lever and the second valve lever may beformed such that the second predetermined distance is equal to or largerthan the fourth predetermined distance.

Furthermore, in another modification of the ninth to eleventhembodiments, the first drive lever and the first valve lever may beformed such that the first predetermined distance is smaller than thethird predetermined distance. In such a case, the torque of the outputshaft (the first drive lever) can be amplified and can be transmitted tothe first valve lever (the first valve). Furthermore, the first drivelever and the first valve lever may be formed such that the firstpredetermined distance is larger than the third predetermined distance.

Furthermore, in another modification of the ninth to eleventhembodiments, the second drive lever, the second rod, and the secondvalve lever may be arranged to satisfy the following condition uponplacement of the second valve in the fully closed state: the anglebetween the third straight line and the fourth straight line is theright angle. Furthermore, the second drive lever, the second rod, andthe second valve lever may be arranged to satisfy the followingcondition upon placement of the second valve in the fully closed state:the angle between the fifth straight line and the fourth straight lineis an acute angle or an obtuse angle.

Furthermore, in another modification of the ninth to eleventhembodiments, the first drive lever, the first rod, and the first valvelever may be arranged to satisfy all of the following conditions uponplacement of the first valve in the fully closed state: the anglebetween the first straight line and the second straight line is theacute angle or the obtuse angle; and the angle between the sixthstraight line and the second straight line is the right angle.Furthermore, the first drive lever, the first rod, and the first valvelever may be arranged to satisfy the following condition upon placementof the first valve in the fully closed state: the angle between thesixth straight line and the second straight line is an acute angle or anobtuse angle.

Also, in another modification of the ninth to eleventh embodiments, thegap forming portion may be formed in the first predetermined shapeportion. Furthermore, the valve drive apparatus may not have the gapforming portion. In such a case, the first predetermined shape portionand the second predetermined shape portion can contact with each other,and the gap between the first predetermined shape portion and the secondpredetermined shape portion cannot be adjusted. However, the first valvecan be driven within a predetermined range by the actuator while thesecond valve is held in the fully closed state with the urging force ofthe urging device.

Also, in another modification of the ninth to eleventh embodiments, thesecond predetermined shape portion may be formed by bending the member,which forms the second drive lever. Furthermore, each of the firstpredetermined shape portion and the second predetermined shape portionmay not be formed by the bending (press forming process) of the member,which forms the first drive lever or the second drive lever. Forinstance, the first predetermined shape portion and the secondpredetermined shape portion may be formed through a cutting process or ametal casting process.

Furthermore, in another modification of the ninth to eleventhembodiments, the actuator may not have the gear member, which isconnected to the output shaft. That is, the output shaft and the motormay be directly connected with each other. Furthermore, the actuator isnot limited to the electric actuator as long as the output shaft of theactuator is rotated about the axis of the output shaft. For instance,the actuator may be an actuator, which is driven by a pneumaticpressure, a hydraulic pressure or any other drive fore.

Furthermore, in another modification of the ninth to eleventhembodiments, the gap forming portion may be placed in the firstpredetermined shape portion instead of the second predetermined shapeportion.

The component(s) of one or more of the above embodiments may combinedwith the component(s) of any other one or more of the above embodimentswithin the principle of the present disclosure. For instance, the valvedrive apparatus of any one of the ninth to eleventh embodiments may beused as the valve drive apparatus of the supercharger of any one of thesixth to eight embodiments. Even with this modification, the advantagesdiscussed in the corresponding one of the sixth to eighth embodimentscan be achieved.

As discussed above, the present disclosure is not limited to the aboveembodiments, and the above embodiments may be modified within the spiritand scope of the present disclosure.

What is claimed is:
 1. A valve drive apparatus installed to asupercharger that includes a first valve, which is rotatable about anaxis of a first valve shaft, and a second valve, which is rotatableabout an axis of a second valve shaft, the valve drive apparatus beingconfigured to drive the first valve and the second valve, the valvedrive apparatus comprising: an actuator that includes an output shaft,which is movable in an axial direction of the output shaft; a shaftportion that is connected to the output shaft and extends in the axialdirection of the output shaft, wherein the shaft portion is driven bythe output shaft; a first member that is placed along an axis of theshaft portion and includes a first contact part and a first engagingpart; a second member that is placed along the axis of the shaft portionand includes a second contact part and a second engaging part, whereinthe second contact part is contactable with the first contact part; afirst valve lever that includes a first valve lever shaft, which isrotatable integrally with the first valve shaft, wherein an axis of thefirst valve lever shaft is parallel to the axis of the first valve shaftand is placed at a location that is spaced from the axis of the firstvalve shaft by a first predetermined distance; a second valve lever thatincludes a second valve lever shaft, which is rotatable integrally withthe second valve shaft, wherein an axis of the second valve lever shaftis parallel to the axis of the second valve shaft and is placed at alocation that is spaced from the axis of the second valve shaft by asecond predetermined distance; a first rod that is rotatably connectedto the first valve lever shaft at one end part of the first rod and isconnected to the shaft portion or the first member at another end partof the first rod, which is opposite from the one end part of the firstrod; a second rod that is rotatably connected to the second valve levershaft at one end part of the second rod and is connected to the secondmember at another end part of the second rod, which is opposite from theone end part of the second rod; and an urging device that is placedbetween the first engaging part and the second engaging part and urgesthe first member and the second member to urge the first contact partand the second contact part toward each other.
 2. The valve driveapparatus according to claim 1, wherein: the valve drive apparatus isinstalled to the supercharger that includes: a compressor that isinstalled in an intake passage, which guides intake air to an internalcombustion engine; a turbine that is installed in an exhaust passage,which conducts exhaust gas outputted from the internal combustionengine, wherein the turbine rotates the compressor when the turbine isrotated upon supply of the exhaust gas to the turbine; the first valvethat is installed in an exhaust flow path, which guides the exhaust gasfrom the internal combustion engine to the turbine, wherein the firstvalve opens or closes the exhaust flow path through rotation of thefirst valve about the axis of the first valve shaft; and the secondvalve that is installed in a bypass flow path that connects between oneside of the turbine, at which the internal combustion engine is located,and an opposite side of the turbine, which is opposite from the internalcombustion engine, in the exhaust passage, while the bypass flow pathbypasses the turbine, wherein the second valve opens or closes thebypass flow path through rotation of the second valve about the axis ofthe second valve shaft; and the valve drive apparatus opens or closesthe first valve and the second valve.
 3. The valve drive apparatusaccording to claim 1, wherein: the valve drive apparatus is installed tothe supercharger that includes: a first compressor and a secondcompressor that are installed in an intake passage, which guides intakeair to an internal combustion engine; a first turbine that is installedin an exhaust passage, which conducts exhaust gas outputted from theinternal combustion engine, wherein the first turbine rotates the firstcompressor when the first turbine is rotated upon supply of the exhaustgas to the first turbine; a second turbine that is installed in theexhaust passage, wherein the second turbine rotates the secondcompressor when the second turbine is rotated upon supply of the exhaustgas to the second turbine; the first valve that is installed in one of afirst exhaust flow path, which guides the exhaust gas from the internalcombustion engine to the first turbine, and a second exhaust flow path,which guides the exhaust gas from the internal combustion engine to thesecond turbine, wherein the first valve opens or closes the one of thefirst exhaust flow path and the second exhaust flow path throughrotation of the first valve about the axis of the first valve shaft; andthe second valve that is installed in a bypass flow path that connectsbetween one side of the first turbine and the second turbine, at whichthe internal combustion engine is located, and an opposite side of thefirst turbine and the second turbine, which is opposite from theinternal combustion engine, in the exhaust passage, while the bypassflow path bypasses the first turbine and the second turbine, wherein thesecond valve opens or closes the bypass flow path through rotation ofthe second valve about the axis of the second valve shaft; and the valvedrive apparatus opens or closes the first valve and the second valve. 4.The valve drive apparatus according to claim 1, wherein: the urgingdevice is made of a resilient member, which has a predetermined modulusof elasticity; one end part of the urging device is engaged with thefirst engaging part; and another end part of the urging device, which isopposite from the one end part of the urging device, is engaged with thesecond engaging part.
 5. The valve drive apparatus according to claim 1,wherein: the shaft portion is formed coaxially and integrally with theoutput shaft; the first member is formed integrally with the shaftportion; the second member is movable relative to the shaft portion; andthe first rod is connected to the shaft portion at the another end partof the first rod.
 6. The valve drive apparatus according to claim 5,wherein: the first member includes an upper member, at which the firstengaging part is formed, and a lower member, at which the first contactpart is formed; and the second member is placed between the upper memberand the lower member.
 7. The valve drive apparatus according to claim 1,wherein: the first member includes a first tubular portion, which iscoaxial with the shaft portion; and the second member includes a secondtubular portion, which is placed on an outer side or an inner side ofthe first tubular portion.
 8. The valve drive apparatus according toclaim 1, further comprising a gap forming portion, which is formed inand projects from one of the first contact part and the second contactpart toward the other one of the first contact part and the secondcontact part and forms a predetermined gap between the first contactpart and the second contact part when the gap forming portion contactsthe other one of the first contact part and the second contact part,wherein an amount of projection of the gap forming portion from the oneof the first contact part and the second contact part is variable. 9.The valve drive apparatus according to claim 1, wherein when an electricpower is supplied to the actuator, the actuator axially drives theoutput shaft.
 10. A supercharger comprising: a compressor that isinstalled in an intake passage, which guides intake air to an internalcombustion engine; a turbine that is installed in an exhaust passage,which conducts exhaust gas outputted from the internal combustionengine, wherein the turbine rotates the compressor when the turbine isrotated upon supply of the exhaust gas to the turbine; a first valvethat is installed in an exhaust flow path, which guides the exhaust gasfrom the internal combustion engine to the turbine, wherein the firstvalve opens or closes the exhaust flow path through rotation of thefirst valve about an axis of a first valve shaft; a second valve that isinstalled in a bypass flow path that connects between one side of theturbine, at which the internal combustion engine is located, and anopposite side of the turbine, which is opposite from the internalcombustion engine, in the exhaust passage, while the bypass flow pathbypasses the turbine, wherein the second valve opens or closes thebypass flow path through rotation of the second valve about an axis of asecond valve shaft; and the valve drive apparatus of claim 1, whereinthe first valve lever is rotatable integrally with the first valve shaftto drive the first valve, and the second valve lever is rotatableintegrally with the second valve shaft to drive the second valve.
 11. Asupercharger comprising: a first compressor and a second compressor thatare installed in an intake passage, which guides intake air to aninternal combustion engine; a first turbine that is installed in anexhaust passage, which conducts exhaust gas outputted from the internalcombustion engine, wherein the first turbine rotates the firstcompressor when the first turbine is rotated upon supply of the exhaustgas to the first turbine; a second turbine that is installed in theexhaust passage, wherein the second turbine rotates the secondcompressor when the second turbine is rotated upon supply of the exhaustgas to the second turbine; a first valve that is installed in one of afirst exhaust flow path, which guides the exhaust gas from the internalcombustion engine to the first turbine, and a second exhaust flow path,which guides the exhaust gas from the internal combustion engine to thesecond turbine, wherein the first valve opens or closes the one of thefirst exhaust flow path and the second exhaust flow path throughrotation of the first valve about an axis of a first valve shaft; asecond valve that is installed in a bypass flow path that connectsbetween one side of the first turbine and the second turbine, at whichthe internal combustion engine is located, and an opposite side of thefirst turbine and the second turbine, which is opposite from theinternal combustion engine, in the exhaust passage, while the bypassflow path bypasses the first turbine and the second turbine, wherein thesecond valve opens or closes the bypass flow path through rotation ofthe second valve about an axis of a second valve shaft; and the valvedrive apparatus of claim 1, wherein the first valve lever is rotatableintegrally with the first valve shaft to drive the first valve, and thesecond valve lever is rotatable integrally with the second valve shaftto drive the second valve.
 12. A valve drive apparatus installed to asupercharger that includes a first valve, which is rotatable about anaxis of a first valve shaft, and a second valve, which is rotatableabout an axis of a second valve shaft, the valve drive apparatus beingconfigured to drive the first valve and the second valve, the valvedrive apparatus comprising: an actuator that includes an output shaft,which is movable in an axial direction of the output shaft; a shaftportion; a first member that is placed along an axis of the shaftportion and includes a first contact part and a first engaging part; asecond member that is placed along the axis of the shaft portion andincludes a second contact part and a second engaging part, wherein thesecond contact part is contactable with the first contact part; a firstvalve lever that includes a first valve lever shaft, which is rotatableintegrally with the first valve shaft, wherein an axis of the firstvalve lever shaft is parallel to the axis of the first valve shaft andis placed at a location that is spaced from the axis of the first valveshaft by a first predetermined distance; a second valve lever thatincludes a second valve lever shaft, which is rotatable integrally withthe second valve shaft, wherein an axis of the second valve lever shaftis parallel to the axis of the second valve shaft and is placed at alocation that is spaced from the axis of the second valve shaft by asecond predetermined distance; a first rod that is rotatably connectedto the first valve lever shaft at one end part of the first rod and isconnected to the shaft portion or the first member at another end partof the first rod, which is opposite from the one end part of the firstrod; a second rod that is rotatably connected to the second valve levershaft at one end part of the second rod and is connected to the secondmember at another end part of the second rod, which is opposite from theone end part of the second rod; an urging device that is placed betweenthe first engaging part and the second engaging part and urges the firstmember and the second member to urge the first contact part and thesecond contact part toward each other; and a gap forming portion, whichis formed in and projects from one of the first contact part and thesecond contact part toward the other one of the first contact part andthe second contact part and forms a predetermined gap between the firstcontact part and the second contact part when the gap forming portioncontacts the other one of the first contact part and the second contactpart, wherein an amount of projection of the gap forming portion fromthe one of the first contact part and the second contact part isvariable.